Why on earth should they go the extra mile of creating a sandboxed UNIX-like environment for the sake of a few power users who desire to run terminal commands which cannot (if they follow their own rules) affect other applications and/or interact in any stateful manner with the filesystem?

Even as a learning experience, why give (power)users the ability to acquaint themselves with a generic platform that is not tied to Apple’s own offerings? It makes no commercial or even pedagogical sense.

Try out iSH: https://ish.app It sounds like it’s what you want. Apple won’t be providing anything even remotely comparable for the foreseeable future, I’m sure.