I think people need to appreciate that the number of developers interested in actually helping with free software maintenance is a subset of the number of developers. And when it comes to Python in particular, that subset is proportionally very small. That's just my anecdotal experience of similar projects in both ecosystems.
Python has been around for a long time and there were some attempts at creating a modern package manager for it. If it were feasible to create uv in Python, it would have probably happened by now.