I can’t answer for anyone else, but it’s not the idea/ theory that is the problem. In most cases, the issue is getting compression low enough to run gasoline. If you mimic the piston shape to the chamber shape, you would need to start out with a piston forging with enough material in the dish area as to not be too thin when it is carved out to finished shape. Every engine is different, and on some, this is probably feasible. Look at a sbc chamber compared to the mopar chamber. Probably a lot easier to do on the sbc because of the deep chamber.
On alcohol or some derivative of alcohol, compression would be higher, and detonation is not an issue that needs a fix.