Heh, first to be clear, I agree that very few things are truly permanent. In fact, I said that in my original question. What I said is that I do not think Python will be going away any time soon, and your examples play nicely into that theme.
The Roman Empire lasted for many centuries, Jovial, Forth, and PL/1 all had very long runs. In fact, they are all still used in some limited capacities today.
http://en.wikipedia.org/wiki/Anicca
python looks like it has staying power
So did the Roman Empire, JOVIAL, FORTH, and PL/1.