The distinction feels entirely academic to me. Managing packages means having a sane way to define the dependencies of software projects, so they can be checked into version control and be installed reproducibly later and/or elsewhere.

I don’t know which problem python intended to solve by separating the two, but it doesn’t occur often in contemporary software engineering work.

Having said that, the point you make is valid and Poetry is a good option, but it feels so maddening having to learn about like seven different tools which all do more or less the same but not quite, and everyone and their mother having an opinion on which is the best. Doesn’t help that there’s an arbitrary yet blurry line where package managers end and environment managers begin.