Part 1 - TVC
The US also ran several programs with TVC:
- F-15 STOL/MTD and ACTIVE.
- F-16 VISTA / MATV. AVEN:
- F-18 HARV (High Alpha Research Vehicle). Overview pdf.
- F-22 (almost 200 produced)
- X-36. (Yaw only.)
- X-44 MANTA (proposed F-22 variant)
(All photos from their respective wiki pages except where otherwise watermarked.)
The F-22 is far from the sole example of US TVC, though the only design to enter serial production.
From the Russian side, you mention the "sheer number of super-maneuverable thrust vectoring Russian fighter jets":
- Su-30 MKI
- PAK FA
But the PAK FA is still deep in development, the MiG-35
probably won't enter production was delayed, and the Su-37 never entered production. To date, only a handful of those three were ever built.
The Su-30MKI was built for India, not Russian forces (see Su-30 for Russian variant). It doesn't use true 3D TVC, but rather fixed 3D TVC: . Explained here:
The Su-35 is the only one [on that list] in widespread Russian service, and only a few dozen of those were produced.
Also notice that the Su-30/35/37 are all part of the same Su-27 family. In fact, the Su-37s were just converted Su-35s. And the MiG-35 is derived from the MiG-29. So there isn't a preponderance of clean sheet designs built with TVC.
In comparison, the US list above includes four different manufacturers and six clean-sheet designs (plus only one derivative), half of which included original TVC solutions (rather than merely retrofitted).
The US had a number of TVC programs itself.
So why does Russia seem like it "put[s] more effort" into TVC?
Beyond flying more TVC fighters, it's also more popular in the news. The Russians have always liked to talk big about their "secret wonder weapons," and US media doesn't discourage them. People devour headlines like "Russian fighters out-turn F-22, US stealth is a hoax, newest US fighter is a turkey." It sells pretty well.
Real design is complex, hard to understand, and easy to deliberately misinterpret.
In contrast, the newest US fighter, the F-35, doesn't have TVC. Since it's A) the only new US fighter since the Super Hornet (other than the aforementioned F-22) and B) replacing so many a/c (F-16, F-18, AV-8B, and probably some A-10s), it means that much of the US fighter inventory won't have TVC. On the other hand, had the JSF program produced 3 completely separate a/c, at least one of those may have included TVC (though unlikely in my view).
Also, Russian TVC employment is ongoing and fresher in people's minds, whereas the US projects above are a bit older and have apparently fallen out of the public consciousness.
So why does Russia use it more than the US?
Russia developed its Su-27 and MiG-29 families in response to the F-15, F-16, and F-18, which were a quantum leap in capability over their predecessors, like the F-4, F-5, Mirage, and Century Series. The F-16 had great sustained turn rate, and the F-15 had powerful engines on a big wing.
But their first engagements with F-15s left the Mirage pilots shaking
their heads. One Mirage ace with fourteen kills described his first
fight with an F-15 whose pilot was just out of F-15 training school to
the author. "The rules were that he could not use his AIM-7s, so the
fight began with a head-on pass. I started to turn and he pulled up
and came around on me. I saw him make three or four mistakes on the
way that I could have easily taken advantage of if he had been in a
regular fighter, but there was nothing I could do to counter the F-15.
He shot me down within forty seconds. I flew home in my Mirage, both
of us feeling very old and out of date." -- Revolt of the Majors: How
the Air Force Changed After Vietnam, by Marshall L. Michel III
The Su-27 was designed to be a bit better. TVC helped to achieve that [or at least tried to].
TVC is useful at very low speeds and high alpha, where conventional control surfaces are less effective. So it's useful for dogfighting---close range, low speeds, lots of turning.
However, using TVC comes at a cost in forward thrust (and drag and weight), which the video above explains. Outside that envelope (where the control surfaces work fine), TVC doesn't see much use.
Unfortunately for TVC, engagement ranges were growing, and within visual range combat was becoming less common, so those kinds of performance parameters were losing utility. New technologies and tactics made it very difficult to get close in the first place: AWACS, improved fighter radars (greater range, look down/shoot down), BVR ID (non-cooperative target recognition), data-fusion, networks, and new long range missiles (higher reliability, improved countermeasure resistance, fire and forget, datalink). BVR combat finally came of age.
Even if you made it to close range, new dogfighting missiles made combat very lethal (see: HOBS, all-aspect engagement envelope, LOAL, HMCS, IIR seekers).
Long-range wasn't the only thing that sidelined TVC. Other designs could also provide control at low speed and high AOA without TVC. The euro-canards are basically supermaneuverable. The F-35 is controllable to ~50 deg AOA and was successfully tested to 110 degrees:
You'll remember that the YF-23 (competitor to the YF-22) doesn't feature TVC. It counted more on higher speeds and better stealth to help keep adversaries at arms' length, rather than tangoing at low speed with TVC. (But note that the YF-23 was also very maneuverable, with a higher sustained turn rate than the F-16, as required.)
So while the US did not neglect TVC, it did opt for different designs and doctrines that had much less use for TVC. It didn't need TVC to attain performance goals, and it doesn't plan on needing that kind of performance very often in the first place.
Now, once the Cold War ended, Russian defense budgets were slashed, and funding for new a/c development dried up, so Russian forces haven't fielded a brand new fighter for over two decades. At least not in meaningful numbers. They're still using the Su-27 and MiG-29 families from pre-1991, just newer variants thereof. So they're not so much 're-emphasizing' super-maneuverability as they are still 'stuck' on it.[That word isn't quite right, but I can't think of a better one.]
Part 2 - Responding to other answers
Please pardon my pet peeves.
1. The F-18 "[emphasizes] maneuvering energy-efficiently, over expending all your energy in tight turns to simply 'get a bead' on your bogey first."
That depends. Compared to an F-16, the Hornet has a lower sustained rate of turn but a much higher AOA (Hornet = 50, F-16 = 15-26.5 degrees, depending on g and loading). The Hornet should never win a fight against an F-16. But it does. Sometimes.
The Hornet can yank its nose, spending that energy, to get the first shot. But if it misses, the F-16 can gradually work its way into a firing position. Rate v. radius.
2. E-M theory as a revolution
Boyd is credited with a lot of things. Humility is not one of those things. Embellishment and self-promotion are. The cult of the man has grown to such proportions in the popular conception that it's difficult to critique him and his ideas without becoming a lightning rod.
While E-M was useful for summarizing some principles of aerial maneuver, it did not invent those principles. Arguably, its real utility was being able to quantify paper designs, not just metal ones.
3. E-M theory in a/c design. "F-15, F-16, and F-18 are designed specifically around energy maintenance in all flight regimes"
I wouldn't say they were "designed around" E-M. It was used to evaluate the designs (after they were already designed), sure, but so were many other metrics.
For example, Boyd wanted the F-15 limited to 5.5 g's because that's what his E-M charts said was most efficient. Needless to say, that didn't happen.
Kinematics are only one aspect of fighter design. Avionics are often more important.
In Korea, F-86s went 10:1 against MiG-15s. Both had the same thrust, but the F-86 weighed significantly more than the MiG, lowering its acceleration/climb rate and altitude.
[Korean fighters aces and Doolittle] felt that the high-technology avionics, while heavy and hard to maintain, allowed the Air Force F-86s to have the high kill ratio despite the Soviet fighters lighter weight. Indeed, Soviet MiG-15 pilots who later examined downed F-86s were extremely envious of the very F-86 systems Boyd and others criticized. --- Revolt of the Majors, 80
It's arguably more accurate to say the F-15 was built around its complex, expensive radar, which Boyd opposed, having never flown an a/c with either radar or missiles.
Boyd was unhappy with both the F-15 and F-16, especially with what they became: high-tech.
4. "US aircraft development has pretty much stopped cold in the mid-late 1980s..."
The F-35 is a HUGE leap over its predecessors (F-16, F-18, AV-8B, F-117): stealthy AESA radar; advanced EW suite; advanced, spherical missile approach and warning; new helmet mounted cueing system and display; integrated FLIR, laser designator/range-finder, and IRST; stealthy, high data rate comms; longer range; DSI; ALIS; lower maintenance electrohydrostatic actuators; lower maintenance, more durable, "baked in" stealth coatings; tightly integrated and fused sensors.
In some ways, the F-35 is more advanced than the F-22. For example, the radar, EW suite, and MAWS are more modern versions of those on the F-22. Some of the F-35's technologies, like coatings and software, will be retrofitted onto the F-22.
5. "[Only] the F-22 and F-35 [entered] production since [the mid-late 1980s]"
The F-22 and F-35 aren't the only US a/c that entered production in the last 26 years.
- C-17 entered production in 1991/92.
- V-22 entered full-rate production in 1995.
- The Super Hornet entered production in 1995.
- Growlers entered production in 2007.
- P-8 Poseidon entered production ~2009.
- E-2D saw initial deliveries in 2010.
- KC-46 entered production a few years ago.
- T-X (new trainer) will likely start production soon.
- JSTARS is looking for a replacement.
- On the helo side, there's KMAX and the proposed S-97.
- The B-21 Raider ("mini B-2") is deep in development.
- And let's not forget all the UAVs:
And there's also the less public ones, like the Doritos over Texas.
Also, "just" the F-35 is understating things a bit, since its 3 variants are intended to replace several different fighters (F-16, F-18, AV-8B, F-117, and probably some A-10s) and over 2,500 airframes in US inventory.
6. The F-22 and F-35 are "decades overdue"
They've only been in development for 15-20 years (depending on how you count), so they can't be "decades" overdue. This is average for modern fighters:
The F-35’s development timeline is also relatively moderate. The Rafale started development in 1982 and introduced in 2001(19 years). The Euro-fighter started in 1983 and was introduced in 2003(20 years). The Raptor started in 1986 and entered service in 2005(19 years). The PAK-FA, an evolutionary aircraft, started in 2001 and will be introduced in 2017(16 years). The Gripen started development in 1979 and was introduced in 1998(19 years). The Hornet was a redesign of the YF-17(9 years) from 1975 to 1983(8 Years) from which the Super Hornet evolved from 1992 to 2000(8 years). The F-35 in comparison to all of these started in 1996 with USAF IOC in 2016(20 years). Source.
7. "...TV simply wasn't ready for operational deployment."
The US experimented with TVC a number of times, but [I'd argue] they deliberately didn't employ it in the "current generation" (ie F-35) because the cost, complexity, weight, and increased maintenance weren't worthwhile for the rare times they'd be useful.
CORRECTION: I misunderstood what s/he meant by "current operational generation." S/he meant F-15/16/18, not F-22 onwards. So they're right that TVC definitely wasn't ready for the F-15/16/18. Otherwise it might have been incorporated into those designs.