It's pretty common to have kept `/usr/bin/python` as Python2. This is the most conservative option and won't break anything that's already running. Anyone who is using Python currently will have already installed Python 3 (or knows how to do this), and is probably using `#!/usr/bin/env python3`. As an OS vendor with many (many...) systems in the wild, you don't want to switch Python versions on people unexpectedly. Especially when it's still pretty painless to keep python2 around even if there is an installed python3.
For anyone that's still using python2 (as a nearby comment mentioned), there is now at least a warning to avoid using the default Python 2.7 (/usr/bin/python). For an OS vendor, this transition takes a long time... but at least it's in process.
Oh, sure, it's definitely not a good idea to change what the unqualified python binary refers to. But I interpreted "refusing to ship an up-to-date global python interpreter with macOS" as meaning that Python3 isn't shipped at all, with the binary name "python3").
Is that the case? If so, I still don't understand the reasoning.
I don’t think anything in macOS (the base OS) requires Python, does it? If not, then, I don’t see why Apple would want to ship any Python with the OS. Let people install the Python version they want and then the users will have to maintain it.
What is the understandable reasoning?