I wonder if the kind of concurrency people have been focused on in these kinds of conversations is really going to turn out to be that important. It seems to me like a lot of the really cpu-intensive problems people are trying to solve are way beyond the scale of a single machine - the kinds of problems you need a big hadoop-style farm to tackle. How many apps are there left that really need maximum throughput in a shared memory architecture?
Programming languages of the future need to enforce thread safety and mutation semantics as well as they do type safety. Functional programming is a step in that direction.
Nobody's necessarily claiming that a concurrent Clojure/Erlang/Haskell app is faster than concurrent C++/Java one, but they're definitely safer and easier to write.