Your argument pretty much kills everything, because there is not much you can't do with a 5 GHz CPU. People have ported Prince of Persia, Civilisation and Lemmings to a 1 Mhz CPU. And they won't stop. Limbo and Eye of the Beholder are next. Why all this effort if you can run those games on other platforms? It's a kind of challenge to port these all-time classics, which were never supposed to run on older platforms. Making the impossible possible. That's what keeps people going.
I was merely pointing the fact that a CPU @ 5G can emulate anything from the 80s/90s/00s without much problem.
The deal is that I am coming out from the point of view that a "new" retro platform is an opportunity to create new games as opposed to port old ones. There are beautiful 8-bit style games made on Unity for example, but it is not the same thing has been develop on a real 8 bit platform. On the other hand, I don't mind the idea of porting because at the end of the day, probably a C256 version of a C64 games will end up being its own thing. Prince of Persa on the Foenix will probably be a different experience than the original or the whole gang of versions that were created on the different platforms of the time. I just find that some peeps keep coming back with the same titles and I wonder why specifically people would like to see an early 3D type game being ported on a 8 bit computer. that's all...