I'm obviously just speculating and handwaving wildly here[1], but ISTM that -- currently -- the limitation here lies mainly in programming languages and semanti

I'm obviously just speculating and handwaving wildly here[1], but ISTM that -- currently -- the limitation here lies mainly in programming languages and semantics. AFAICT all of the non-traditional machine models require radically different programming paradigms[2] and we still aren't quite at that point where gaining more performance is painful enough that the necessary research/innovation will happen. That's assuming that it's even possible. Obviously, any model of computation places some limitations on what can happen and all information transfer (thus computation) is still limited by the speed of light. Some things are just going to remain out of reach forever and not even Quantum Computers are going to help. [1] As I suppose we all are. C'mon we're talking about predicting the future here. [2] If you want a practical example, look at the PS/3 Cell processor. I can't claim to have done any 'native' programming for the PS/3, but I've heard (from very clever people that I trust) that it was quite alien and required radically different program structure from what one is used to. And that architecture isn't even that different from 'normal' architectures.