Pip is suitable for use by developers working in python, setting up python workspaces with python sources and python dependencies, but it's a UX fiasco for an end-user who just wants to run a black box application and not have to care.

In my particular case the "application" was in fact interactive bootstrap/install scripts for a large, proprietary blob which wouldn't have been suitable for publishing on PyPI, anyway. Setting up a separate, possibly authenticated PyPI instance, and then training end users how to use it, vs just shipping everything together in a single package? Total non-starter.