Do you remember the reason? I spend most of my time in the Java and JS ecosystems where one tool does both jobs.
In my mind they’re pretty heavily linked. But that may be based on not experiencing the opposite. At least not as far as I can remember.
This probably represents it fairly accurately, though I had to search for it and haven't watched: https://www.youtube.com/watch?v=QzxDIKbOp_4
Travis Oliphant is a founder of Anaconda and one of the most important people behind NumPy, SciPy etc.
Separation of concerns. They just wanted pip to be a good installer and let package managers* use pip. But uv didn't end up doing that either.
* or workflow tools as they're called here https://packaging.python.org/en/latest/guides/tool-recommend...