There is no requirement to hold the trigger and then release it after the slide closes. If you're fast enough (no one is even close) you can release it during the slide cycle.But there is more than just the speed of cycling involved. Its things like trigger reset, and feel as well. Once the slide closes, the trigger group has to move enough to reset, and the shooter has to time the release and next pull differently than on a DA revolver.
There is no reason that a semi-auto couldn't be shot at a rate very close to the cyclic rate of the pistol if the shooter can move his trigger finger that fast. To do so he would have to shoot about twice as fast as Jerry Miculek's DA revolver record and about 50% faster than the fastest splits being recorded today with autopistols.
This is simply not true. 0.10 second splits (and even faster) are not unheard of in competitions using autopistols but Jerry Miculek's record with a DA revolver is about 20% slower than that. Since it's a world record it's a reasonably safe bet that no one is shooting DA revolvers faster than that.The top speed shooters are not faster than the auto is mechanically, but they are faster than the auto is functionally, compared with a tuned DA revolver, in their hands.
This is really the crux of the matter. You can poke around on the web and find folks talking about documented splits with autopistols down around 0.1 and even 0.09 seconds. No one has ever been documented pulling the trigger on a DA revolver anywhere near that fast. Not even Ed McGivern or Jerrry Miculek.
The bottom line is that as long as a human is pulling the trigger an autopistol is going to shoot faster than a revolver. There is simply no evidence that a human can pull a DA revolver trigger fast enough to outpace what a human can do pulling an autopistol trigger.
Furthermore, based on the cyclic rates of autopistols, it is apparent that no humans are coming even close to shooting as fast as an autopistol is actually capable of. They would need to go about 50% faster than what is being done today.
So yes. THEORETICALLY a revolver's mechanism could be driven faster than an autopistol can cycle but no one has ever been able to demonstrate that they can shoot one that fast. Even the two revolver shooters who are universally accepted to be the best and fastest over the last century couldn't do it.
For those who STILL doubt this, there was a History Channel show awhile back called Extreme Marksman. On it, Jerry Miculek bumpfired a 1911 demonstrating conclusively that he could operate the the autopistol's mechanism faster than he was able to fire a DA revolver when he set his revolver record.