I am a Computer Hardware professional. I started working with computer technology in the early eighties. I have seen the evolution of technology starting with closed platforms like the game console era and then the move toward open platforms like the Home Computer Golden Age. In the last 5 or 10 years, I have witnessed technology changes that are slowly moving away from open hardware designs towards hardware that is locked down and can’t be modified by the user.
In the sense that the card edge connector plugs directly into a slot on the motherboard instead of being connected via a cable, M.2 drives are more like NES cartridges than 2.5" drives are.