On the contrary, I think that we haven't exploiting sequential machines to their full potential, and what's "holding us back" is all this theoreticism and overabstraction. There likely is a point where concurrency is really necessary, but one only has to look at the demoscene, full of people who have never formally studied CS, to see something closer to what hardware can really do -- and then wonder how so many others working in software, with formal backgrounds and extensive education in CS, couldn't.