Npm is a pretty good example of what pip should be. Npm has had to compete with other package managers for a long time but has remained the standard simply because it actually has all the basic features that people expect out of a package manager. So other package managers can spin up using the npm registry providing slightly better experiences in certain ways, but npm covers the basics.
Pip really does not even cover the basics, hence the perpetual search for a better default.
Pip isn't part of the standard library; the standard library `ensurepip` (called from `venv`) includes a vendored wheel for Pip (https://github.com/python/cpython/tree/main/Lib/ensurepip/_b...), and imports Pip from within that wheel to bootstrap it. (Wheels are zip files, and Python natively knows how to import code from a zip file, so this just involves some `sys.path` manipulation. The overall process is a bit complex, but it's all in https://github.com/python/cpython/blob/main/Lib/ensurepip/__... .)
This is why you get prompted to upgrade Pip all the time in new virtual environments (unless you preempt that with `--upgrade-deps`). The core development team still wants to keep packaging at arms length. This also allows Pip to be developed, released and versioned independently.
The problem is that in the python ecosystem there really isn't a default de facto standard yet at all. It's supposed to be pip, but enough people dislike pip that it's hard as a newcomer to know if it's actually the standard or not.
The nice thing about putting something like this on a pedestal is that maybe it could actually become a standard, even if the standard should be simple and get out of the way. Better to have a standard that's a bit over the top than no standard at all.