The fact that this exists shows that there is a serious problem in the python ecosystem. I'm sure it solves a real problem, so I'm not knocking the author. It's more of a "state of our industry" problem.
pyenv is all you need. it manages python versions and python virtual environments. you can create and destroy them just as easily as git branches.
pyenv + good ol' requirements.txt is really all you need.
if your env dictates containers, it's even easier to work with. FROM python:version and done.
I think having a very widely accepted and supported default would let the community rally around it and improve the experience and documentation (though I am not a fan of the centralized hosting that npm and cargo push, I much prefer the go approach, but we are already there with PyPI)
pip, uv, poetry are all analagous. they ensure the correct packages are installed. we have some internal apps that devs decided to start with poetry and it has some nice ergonomics ... but on the other hand I find the simplicity of a requirements file to be so ... simple. People get caught up on the file, too, but really its just a convention. you can call it whatever you want, deps.txt, deps.foo, packages.bar ... its just a plaintext file with newline delimited packages. since its "just a file" and "just unix" this has the added perk of being able to cat many files together and use that with pip. it's all just lines of text, pip does not care.
pyenv + pip works. pyenv + poetry works. pyenv + uv works. those become inconsequential decisions you can make on a case by case basis and try or forget as needed.
I agree that there is a really nice simplicity to requirements.txt but I've myself enjoying uv enough to just fully embrace it (and not farm out to uv pip) and as a result I now find myself in pyproject.toml land.
I wouldn't recommend it for something with hundreds of dependencies, but I also wouldn't recommend having hundreds of dependencies.
Poetry has messed up packages more often apt ever did, in my use cases. So far using apt as by package manager has failed me exactly zero times.
Absolutely, but that's true for pretty much all the package managers, for all languages. They all break at some point.
One thing I would note is: Don't install your dependencies with apt in a development environment, you need to have a clean environment to avoid dragging unneeded dependencies into your production environments. That does mean that you need to find the exact version of your dependency in Debian, but it's a good exercise and ensures that you're mindful of your dependencies.
Be mindful, be prepared is good advise, in all aspects of life really.