Here, try this once a week, for about 3 weeks:
Warmup until your legs feel a bit open, no minimal time. Then, while seated with hands on the drops or aero bars, shift into super easy gear like 39x19/21. From a slow speed, accelerate to a maximum pedaling cadence for 30 seconds. Recover for a full minute.
Repeat for a total of 6 efforts. Ride steady for 15 minutes, then repeat.
See what that does for your top end cadence, outside of making you want to puke.
I'm all for trying something new... I'll give it a shot and see what happens. My local group thinks I spin like a madman.. I just want to spin faster.