Java? Nope, you're getting a fundamental change in Valhalla C++? Nope, new language edition every few years with fundamental changes C? C23 has a number of fairly fundamental changes, expect more in the next language revision
I think your sense of causality is backwards here. These languages are getting fundamental changes because they're being widely used. That is what motivates and drives the change. Languages with no users don't need to change.
But most such languages handle much better the compatibility with legacy applications.
Python is the main culprit in most cases when I see conflicts between various software packages that insist to use only a specific version of their dependencies. This is why I have to keep installed many versions of Python, and the Linux distribution that I use must take care to prevent interference between those Python versions.
That's fine, but that's clearly not what I'm talking about.
Languages like F#, Elixir, etc. don't undergo fundamental changes. Yes, every language evolves. But for Python, we're talking about grafting literally fundamental stuff on top of a language not designed for any of these things.
For example, if someone went and redesigned Python to solve its warts, you'd basically end up with F#.