[temp51723]

It doesn't. You stick to the version of those libraries at work with that version of the compiler- like every other language.

[ObscureScience]

The difference is that most other language are backwards compatible to a fault (it's hard to have the stability cake and eat improvements)

[ubercore]

That's fine in a vacuum, but I feel like you'd very quickly run into the need for a security update, or some external API that changes, etc. You can't ignore all externalities, usually.