Is there any chance that a project like RustPython could supplant CPython?
Depends...
There are already other implementations. But CPython is the reference implementation. That's part of why we're only now seeing optimizations that reduce code clarity for reading. (i think, dont quote me on this)
No need to quote you, but GvR himself [0]. That's the Faster CPython initiative, which has been ongoing for about 2 or 3 years I think. 3.11 got some nice speedups from it, and 3.12 is on its way to get more. [1]
[0] https://github.com/faster-cpython/ideas/blob/main/FasterCPyt...