A number of technologies have been banned from F1 because they were too good. (Other sports, too, like aluminum bats in major league baseball.)

When an AI bot is driving the car, are you still going to watch F1?

Well, how far do you want to take that argument? One could argue the last time high performance piston engine engineering actually mattered was in the aero engines of the 1940'ies. Then you had the might of nation states pouring resources (directly, or indirectly through buying lots of them) into making the absolutely highest performing (in terms of power/weight) engines. With some consideration to reliability, of course, and relatively little consideration to cost. Producing masterpieces like the mighty R-2800.

After that the serious development money went into turbines. Sure, piston engine development didn't stop, but the development going into "performance at any cost" was a pittance compared to other priorities.