I guess one thing Conda has that the pip ecosystem doesn't is that it supports installing non-Python shared libraries like libcurl on their own. Is that an advantage? (We absolutely could replicate that in the pip ecosystem if that was worth doing, and it's even not totally unprecedented to have non-Python binaries on PyPI.)
With respect to versioning, I think pip should be way more strict. It should force you to freeze dependency versions before uploading to pipy, not accept "libxyz > 3.5", but require a fixed range or single version. That would make packages much less likely to break later because newer versions of their dependencies don't work the same way anymore.
The solution is: don't mix your package environments. Use a conda environment. Just like in Linux, you'd use a container. If you wait for the Python steering committee to fix pip you'll be waiting a long time.