One other aspect of this. Unification of interface would let us modify the PyPI header that currently says “pip install X” as the install command for packages, to be generic. And provide advice for projects on how to write their “how to install” instructions in a generic form.
Conversely, if we don’t unify interfaces, how do we address this aspect of what users see as “too many options” - assuming we want to modify the current approach which implicitly prefers the pip/PyPI/wheel toolset over other integrators?