Even scalable web-whatever is often IO-bound... of my several apps in production, there's only one where CPU is a serious concern, and I run that one on PyPy. cPython is fine for the others.
I'll go so far as to say that we haven't done enough with making things fast on multicore processors except with IO-bound tasks. The current architecture of multicore processors stinks for achieving anything but the "embarrassingly parallel."
