Hardware level approaches to making C more secure are in the works at Intel. Hardware assisted bounds checking and the like...http://en.wikipedia.org/wiki/Intel_MPX

The main thing that will finally convince people that a high-level of abstraction is OK for OS level programming is for someone to get off their a$$ and build one. (That's actually usable. It would have to be SO usable that people could quickly build out the new user code to make something like *nix or windows seem like more of a hassle in contrast. That's such an insanely tall order...not sure how you get there.)

I think that the best you'll ever be able to do is to build systems with frameworks that are safe(r). People won't give up C because it makes them feel smarter. The pile of code for C based systems will be with us forever. A new system would have to be able to do all that AND be safe.