I agree uv is great but let’s not get carried away here. Poetry is good, pip was fine for many use-cases after they added native lock files.

if you are working on one tiny project on your machine that pips in four packages you probably think pip was OK.

Circa 2017 I was working on systems that were complex enough that pip couldn't build them and after I got to the bottom of it I knew it not my fault but it was the fault of pip.

I built a system which could build usable environments out of pre-built wheels and sketched out the design of a system that was roughly 'uv but written in Python' but saw two problems: (1) a Python dependent system can be destroyed by people messing with Python environments, like my experience is that my poetry gets trashed every six months or so and (2) there was just no awareness by the 'one tiny project on your machine that pips in four packages' people that there was a correctness problem at all and everybody else was blaming themselves for a problem and didn't have a clear understanding of what was wrong with pip or what a correct model for managing python dependencies is (short answer: see maven) or that a 100% correct model was even possible and that we'd have to always settle for a 97% model. The politics looked intractable so I gave up.

Now written in rust, uv evaded the bootstrap problem and it dealt with the adoption problem by targeting 'speed' as people would see the value in that even if they didn't see the value in 'correctness'. My system would have been faster than pip because it would have kept a cache, but uv is faster still.

Poetry and friends are so bad that many people continued just using pip -r requirements.txt despite knowing about this other stuff

Poetry having users isn’t the metric for success. pip having way less users is.