The point is that it is threading/simultaneous execution that is the big deal. A language designed around some 'concurrency not parallelism' slogan has missed the boat... concurrency was never the problem that needed to be solved.

For instance in golang the only support the language has for simultaneous execution is a threadsafe queue -- that's all. And the runtime libraries only have variations on mutex that you even have to manually create locks and manually remember to unlock them. This is extremely weak sauce for a 'concurrent' language.