This is a delicate issue. As guido stated (https://discuss.python.org/t/pep-703-making-the-global-inter...):

> If there’s one lesson we’ve learned from the Python 2 to 3 transition, it’s that it would have been very beneficial if Python 2 and 3 code could coexist in the same Python interpreter. We blew it that time, and it set us back by about a decade.

So it's not so easy to decide to go with again 2 different versions of Python.

I understand how caution they are.

However, this commitment from Meta, complemented with MS financing Guido, and the quality of Sam Gross proposal makes me optimistic.