[loupgaroublond]

Most of it's been covered here, but another point is that for every mainstream language that doesn't seem to be so revolutionary, there are lots of little languages that never made it. In order for there to be lots of innovation, we also need lots of iterative steps in languages. This helps the less than genius programmer, the ones that get that templates in C++ are good, but would never bother learning lisp, get the new ideas in incremental steps.

Also, something you see quite a lot is innovative concepts built onto existing languages via libraries that then get integrated into new languages.