If these were just ABI changes, packagers would simply re-package under a new ABI. Instead they specify ranges of versions in which "it works". The upper end often doesn't include the last python version and may be specified as "up to 3.x.y" even.

Sure I'm not that knowledgeable in this topic (in python). But you're telling me they go to the lengths of supporting e.g. 3.9-3.11.2, but out of lazyness won't just compile it to 3.12?

I can only hypothesize that 3.9-3.xxx had the same ABI and they don't support multiple ABIs out of principle, but that sounds like a very strange idea.