There is zero chance of that happening. Guido van Rossum (and other key figures in the Python community) have spoken very candidly for years about the mistakes they made in the 2-to-3 migration and their decisions in the year since have demonstrated their commitment to not repeating these mistakes.
I was curious about these comments and did a small web search. I found a video interview from May 21, 2021 [1] and have pasted some excerpted quotations from it from Guido van Rossum below for others who are curious.
“Python 4, at this point whenever it’s mentioned in the core development team, it is very much as a joke… We’ve learned our lesson from Python 3 vs 2, and so it’s almost taboo to talk about a Python 4 in a serious sense.”
[...]
“I normally talk about that as a mistake, because Python was more successful than the core developers realised and so we should have been much more aware and supportive of transitioning from Python 2 to Python 3”
[...]
“I’m not thrilled about the idea of Python 4 and nobody in the core dev team really is – so probably there never will be a 4.0 and we’ll just keep numbering until 3.33, at least”
[...]
“We now have a strict annual release schedule, so after 3.10 will be 3.11 and after that will be 3.12, and so forth. We can go up to 3.99 before we have to add another digit. Adding another digit is not completely trivial, but still much better than going from 3 to 4."
