The analogy with compiled languages such as C is not a good one. In the event of an incompatible change in the syntax of a compiled language, you only have to care about it when you need to change it; in the case of an old locally-built program that may well be as close to never as makes no odds. In the event of an incompatible change in the syntax of an interpreted (or compiled-on-the-fly or whatever) language such as Python, you have to care about it the next time you need to run the program.
I'm not bashing Python; I happen to think the trade-off here is worth making in a lot of cases. But C and other compiled languages just aren't a good target for comparison here.