I think it makes sense given that people using python to write applications are a minority of python users. It's mostly students, scientists, people with the word "analyst" in their title, etc. Perhaps this goes poorly in practice, but these users ostensibly have somebody else to lean on re: setting up their environments, and those people aren't developers either.

I have to imagine that the python maintainers listen for what the community needs and hear a thousand voices asking for a hundred different packaging strategies, and a million voices asking for the same language features. I can forgive them for prioritizing things the way they have.