Braking parachutes were standard on first-generation jetliners, but have since fallen almost entirely out of use except on military aircraft; essentially the only civilian aircraft nowadays to still carry braking parachutes are some Learjets, which have emergency parachutes to help prevent an overrun during a landing or high-speed rejected takeoff if the runway is slippery or if one of the aircraft’s primary braking systems (reversers, spoilers, wheelbrakes) malfunctions.
Given the relatively frequent occurrence of runway overruns (often resulting from slippery runways or from takeoffs rejected near or after V-1), why aren’t most civilian aircraft (especially large, heavy ones, which need lots of runway to slow down even under ideal circumstances, and need all the help they can get if circumstances are less than ideal) equipped with emergency braking parachutes to help prevent overruns?