I don’t mean at all to imply scipy and co are flashy but rickety pieces of software. I think it’s a testament to their quality that such libraries have reached a broad and diverse audience.

I think the foundational libraries of the scientific Python ecosystem are definitely well taken care of. I think a lot of that care comes from “brute forcing” the ecosystem to make it work, eg distributing native compiled C/Fortran code seamlessly on a bunch of platforms with entirely new (at the time) package managers like conda, or wholly new scientific distributions of Python. My observations are more to do what’s built atop them.