> pip could implement parallel downloads, global caching, and metadata-only resolution tomorrow. It doesn’t, largely because backwards compatibility with fifteen years of edge cases takes precedence. But it means pip will always be slower than a tool that starts fresh with modern assumptions.

what does backwards compatibility have to do with parallel downloads? or global caching? The metadata-only resolution is the only backwards compatible issue in there and pip can run without a setup.py file being present if pyproject.toml is there.

Short answer is most, or at least a whole lot, of the improvements in uv could be integrated into pip as well (especially parallelizing downloads). But they're not, because there is uv instead, which is also maintained by a for-profit startup. so pip is the loser