The inspecting of stack frames is used by the logging library, and by most unit testing libraries. There are dozens of these small features which are challenging, and if you remove all of the challenging ones, you end up with something where pretty much no existing Python can run.
People have tried, pypy started with that goal before it became clear it wasn't practical.
How about an implementation of python that doesn't let you do fancy things like that that are not needed in production?