[chucksmash]

I can't speak for all of those languages, but this functionality is often provided at the web framework level in Python and it fits quite nicely there. Since your web framework typically also knows where you are storing your passwords, you can do nice things like increase the number of bcrypt rounds in a settings file and have users transparently migrated as they login which I'd assume doesn't really work at the language level.

Still, a pragmatic answer and, given PHP started life as a web framework, fitting :).