There are versions of Python without RC: https://www.python.org/download/alternatives/. There is no doubt that Python would be better off without RC, the problem is that Python extensions rely on RC. So CPython (the main python implemenation) can't just do the switch.

If you want more information about this topic, there is a nice talk by Larry Hastings: https://www.youtube.com/watch?v=pLqv11ScGsQ