I think the most significant boundary is given by the question: "is there a plan to support new minor versions of Python?" It sounds like there is not.
There may be non-zero maintenance work happening, but a project that only maintains support for old versions and will never adopt new ones is functionally one that the ecosystem will eventually forget about. Maybe you call that "under active development" but my response is "ok, then I don't care whether it's under active development, I (and 99.9% of other people) should care about whether it's going to support new minor versions."
On the other hand, if you don't support new minor versions day one, but you eventually support them, that's quite different.
> I think the most significant boundary is given by the question: "is there a plan to support new minor versions of Python?" It sounds like there is not.
There is literally a Python 3.12 milestone in the bug tracker.
> my response is "ok, then I don't care whether it's under active development, I (and 99.9% of other people) should care about whether it's going to support new minor versions."
It sounds a lot more like your actual response is "I don't care about pypy".
Which is fine, most people don't to start with. You don't have to pretend just to concern-troll the project.
More specifically, the Scientific Python community through SPEC 0[0] recommends that support for Python versions is dropped three years after their release. Python 3.12 was released in October 2023[1], so that community is going to drop support for it in October 2026.
Considering that PyPy is only just now starting to seriously work on supporting 3.12, there's a pretty high chance that it won't even be ready for use before becoming obsolete. At that point it doesn't even matter whether you want to call it "in active development", it is simply too far behind to be relevant.
[0]: https://scientific-python.org/specs/spec-0000/
[1]: https://www.python.org/downloads/release/python-3120/