It's interesting to note that PEP 582 (i.e. __pypackages__) mode used to be the PDM default -- and was sort of its flagship feature -- before being made opt-in with 2.0 release, the explanation being that the PEP had stalled, and that editor and IDE support for virtualenvs is much better (https://www.pythonbynight.com/blog/using-pdm-for-your-next-p...).

If you read through the discussion on the Python forum, one of the counterarguments to the PEP is that "If existing tools can already support this, why do we need a PEP for it?" But presumedly a PEP would help push the ecosystem to accommodate __pypackages__, and to solve the aforementioned problems (like broader editor and IDE support).

For what it's worth (as someone that builds Python tooling full-time): I'm generally a fan of moving to a node_modules-like model.