Another is that a microwave doesn't operate at a set pressure, so even the same model will behave differently at different evelations.

That's true of pretty much all cooking (and baking) except when using a pressure cooker, so it's kind of a given - people learn to cook given their local pressure and humidity levels.

But then again, cooking is poor man's process engineering - what you do when you don't particularly care about quality and consistency, or at least don't have access to hardware and methods to ensure them.

Yeah so the instant pot is an exceptionally good kitchen tool for sharing recipes with others in a reproducible way.