Is it? I would have thought this is still in line with their goals. Your individual projects' venvs will still be fully separate.
No, they're saying that they have one venv they use for everything (i.e., it's basically a working "pip install --user").
I think it's a good thing that pip finally decided to refuse overwriting distro package paths (the alternative is far worse) but making "pip install --user" not work as well doesn't make sense.