What's wrong with the approach is that it goes against basic principles of the Python ecosystem. Python has always followed the policy of standardising mechanisms and allowing implementations to develop and peacefully coexist. The Python way fosters diversity of implementations. Note that uv itself would not be a reasonable project if not for Python's approach to diverse tooling.
You cite good examples where other languages have chosen to standardise tooling. We can discuss the pros and cons of that choice. But it is a choice, and Python already made a different choice.