We've got pip, conda, poetry, etc, all with their different advantages and disadvantages. I think the only thing that could solve the fragmentation problem is an authoritative solution from the Python Foundation itself. Cohesion is what's needed, not more options.
The thing is that a comprehensive Python packaging solution would need to include packaging of C and C++ extensions at least. And that's not simple. In the meantime, Guix is establishing itself as a cross-language package manager wich can define an own distro, or run on top of a POSIX system like Debian, Ubuntu or Arch. And it is rock solid and currently features around 17,000 packages. A new Python packaging solution would have a hard time competing with that.
I believe pip and conda already support native modules. I'm not saying it was easy to get there, but it's a solved problem at this point. The problem that still needs to be solved is project-scoped dependencies vs system-scoped dependencies. Virtual envs are a hacky workaround that causes all sorts of problems. I'm convinced Python has been one of the major drivers of Docker's adoption, because any given module is concerned with the entire system.