Many competent contributors have left or were silenced by the politicians. PyPI had multiple severe vulnerabilities. pip has no adequate story for the scientific ecosystem. Building from source via pip usually fails, unlike around 2010 when it usually worked.

The only thing that prevents lock-in is the religious zeal of most Python users to use anything presented by the PSF high priests, not technical merit.

The reason uv exists is the utter incompetence of PyPA.