> None of this requires Rust.

Indeed. As demonstrated by the fact that pip has been doing exactly the same for years.

Part of the reason things are improving is that "tries PEP 658 metadata first" is more likely to succeed, and at some point build tools may have become more aware of how pip expects the zip to be organized (see https://packaging.python.org/en/latest/specifications/binary...), and way more projects ship wheels (because the manylinux standard has improved, and because pure-Python devs have become aware of things like https://pradyunsg.me/blog/2022/12/31/wheels-are-faster-pure-...).