Many ideas are being added to recent versions of pip that are at least inspired by what uv has done — and many things are possible in uv specifically because of community-wide standards development that also benefits pip. However, pip has some really gnarly internal infrastructure that prevents it from taking advantage of a lot of uv's good ideas (which in turn are not all original). That has a lot to do with why I'm making PAPER.
For just one example: uv can quickly install previously installed packages by hard-linking a bunch of files from the cache. For pip to follow suit, it would have to completely redo its caching strategy from the ground up, because right now its cache is designed to save only download effort and not anything else about the installation process. It remembers entire wheels, but finding them in that cache requires knowing the URL from which they were downloaded. Because PyPI organizes the packages in its own database with its own custom URL scheme, pip would have to reach out to PyPI across the Internet in order to figure out where it put its own downloads!