This is an old thread where discussion came to an end, let’s not resurrect it, especially with subjective complaints.
If you have new concrete ideas to address the problem then please make a new thread so they can be discussed directly. But perhaps also worth reading:
https://discuss.python.org/t/allowing-multiple-versions-of-same-python-package-in-pythonpath/2219
And maybe: https://discuss.python.org/t/idea-allow-installation-of-package-local-dependencies/13169
Generally it seems changing Python and/or Python Packaging to support multiple versions of the same package would be massively breaking.
But if you have some concrete ideas about standards that could be implemented between libraries some people may find that interesting.
A proposal I would strongly support is a method for library authors to easily update their metadata after release to an index, but it would need to be well thought out not to break existing tooling or reasonable assumptions.