FYI there’s a PEP for this:
It’s still in draft because there’s been a lack of consensus/activity in terms of the exact limitations that would be acceptable on deletions in PyPI.
(There’s also an argument that this PEP is procedurally irrelevant, since PyPI can decide as a manner of policy to limit deletions without a PEP. But I think the ideas in the PEP are worth discussing even if the form of action doesn’t ultimately require a PEP 
)
PEP discussion is here as well: PEP 763: Limiting deletions on PyPI