C has been around since 1972 and is just as relevant as ever even as the popularity of C++ wanes. Python has been around since 1991 and is growing in popularity.
There is a trick to figuring out which technologies will stick around for the long haul, and it is one which most developers don't even think to try and hone.
My career advice would not be to not specialize in programming languages but to learn to distinguish programming trends from programming fashions and invest (with training/picking the right job, etc.) accordingly.
I doubt there is going to be much call for people with experience in Mongo in 5-7 years' time, for instance, but Postgres? Hell yeah. I predict increased demand for F#, too, but not so much for, say, Java (even though it won't go away).