Above is from a cutaway for the GE9X. The gap you see is not empty. Marked in yellow is the nozzle guide vanes (they have removed most of it for illustration purposes). Those vanes are analogous to compressor stator stages, but for the turbine.
Below is a snippet from a much, much higher resolution RR Trent 500 cutaway with impressive details.
On the funny side, here's a thumbnail from RR's own YouTube channel:
Absolutely bonkers exhaust.