Silicon is here to stay for the foreseeable future, and for a very simple reason. While we have many advanced possibilities with germanium or carbon nano-tubes or other such advanced processes, silicon is still the cheapest by such a magnitude that it wins out in performance per dollar.
I'm not saying it will always be that way, but rather there is a large gap so, barring incredible breakthroughs, silicon's got at least a decade or so left.
Why couldn't we have incredible breakthroughs tomorrow? Well, we could, but they've been working on non-silicon tech for at least thirty years now- and we are still using silicon.
