The problem mentioned with pyenv is that people accidentally develop/test on the wrong version of python itself. But that's specific to pyenv, and I don't actually see where the article discusses problems with venv. So again: What exact steps would a team take using just pip+virtualenv or pip+conda (the comment you responded to didn't mention pyenv or venv) that would lead to production outages?
It feels like you've determined there's nothing wrong with pyenv, pip, and virtualenv so any issues brought up, you will reject.
If that's not the case, here's the issue - someone used pyenv and did not exactly specify the python type - I believe we were on 3.9 and prod was 3.9.11 and the current python version was 3.9.12. There was a downstream package that had an OS dependency - I believe it was pandas - that conflicted and needed to be updated locally to work with 3.9.12. This broke and raised an error in production that was not reproducible locally - and when you deploy on AWS, reproducing can be a pain in the butt. I'm sure if the data scientist had used perfect pyenv, virtualenv, and pip commands; we would have caught this. However, they're very complicated - especially for people who focus on math - so requiring full knowledge of these tools is unrealistic for most data scientists.
> It feels like you've determined there's nothing wrong with pyenv, pip, and virtualenv so any issues brought up, you will reject.
Alternatively, I'm rejecting your claims because you keep making them and then not providing evidence. Now that you've actually described the problem, I can agree that that's a footgun, and pyenv should start to strongly discourage setting a global version in much the same way that pip has started to protect against people using `sudo pip install` to trash their systems.