Fundamentally we still have the flat namespace of top level python imports, which is the same as the package name for ~95% of projects, so I'm not sure how they
could really change that.
But you can if you want have a non-flat namespace for imports using PEP 420 – Implicit Namespace Packages, so all your different packages "company-foo", "company-bar", etc. can be installed into the "company" namespace and all just work.
Nothing stops an index from validating that wheels use the same name or namespace as their package names. Sdists with arbitrary backends would not be possible, but you could enforce what backends were allowed for certain users.