It comes up again and again, because people don't realize that solutions already exist(ed) and they don't spend the time to figure things out.

I have managed reproducible Python services and software for multiple years now. This was solved already before uv, although uv does it faster and maybe offers a bit more comfort, although I abstract away such tooling using a simple Makefile anyway.

The reason you are having such a bad time getting random Python projects to work out of the box is, because people creating them did not spend the effort to make them reproducible, meaning, that they do not ensure the setup has same versions and checksums of every direct and transitive dependency. This can be facilitated using various tools these days. poetry, uv, and I am sure there are more. People are just clueless and think that a requirements.txt file with a few loose versions slung in is sufficient. It is not, and you end up with not working project setups like in those cases you refer to.