Why? Installing python and php can be done in 2 seconds with brew, and you have control over what you install instead of using whatever is in the system, with deprecated versions, etc. It is actually much better now. System tool should be left to the system.

Virtually zero professional developers that I know use built in Python or PHP. Maybe it’s good enough for occasional scripting purposes, though.

I think it’s better for developers to not have conflicting system distributions.

Though for a while there having built in interpreters was great for kids and learners.

I much prefer installing it myself, with the required version for my project and at a known and common location.

That's fair enough. It may be less of an issue for experienced developers, but for those looking to learn the craft, it's one more barrier.

if you install commandline tools there's

/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/