> The problem is that it is lagging behind enough that it is falling out of the support window for a lot of libraries.

Which is a concern for those libraries, I've not seen one thread criticising (or even discussing) numpy's decision.

> Should tooling give a big fat warning about it being essentially unusable if you try to use it with the 2026 Python ecosystem? Also yes.

But it's not, and either way that has nothing to do with uv, it has to do with people who use pypy and the libraries they want to use.