For arbitrary binary dependencies, however, I contend that reconciling
the two different use cases is simply infeasible, as pip and venv have
to abide by the following two restrictions:

To be clear, what's a good example of a common non-science PyPI package that has an "arbitrary binary dependency"? psycopg2?

For many end users just running things locally (especially beginners
and non-developers), using conda will be the quickest and easiest way
to get up and running.

Conda/Anaconda is an alien world right now to most non-science people (including me)

Working in an alien world, is never the "quickest" or "easiest" way at first, but I'm curious to try.

Some PyPA people actually need to try using it for real, and get comfortable with it.

>> sometimes mean needing to build components with external dependencies from source

you mean build once (or maybe after system updates for wheels with external binary deps), and cache as a local wheel, right?