I don't see anything replacing git any time really. Though again people said that about gcc in the early 2000s. Git has more usage than gcc had across all platforms.
Traditional Linux userspace provides barely any API/ABI compatibility at all so the fairly stable kernel ABI doesn't really provide much in most cases. Android has the API level system with quite strong backwards compatibility but that's non-existent for the desktop Linux stack.
Even on a server, there's not much backwards compatibility beyond the libc, and glibc backwards compatibility has the MASSIVE caveat of not applying to code being able to run on older glibc than you used to build. Android libc gates additions/changes behind API levels for that.
Unless you actually care about running unmaintained software and legacy builds you can't redo, absolute ABI/API compatibility isn't really needed. Just needs to be almost there with enough adoption that developers actually support it.