Doesn’t the “missed step detection” on the Prusa printers already achieve a lot of that? I think it monitors the current to the motor and flags any abnormal behavior, without needing extra hardware on the motor.
That’s not to knock the value of positional feedback, which is clearly superior, but just to say that I don’t think this idea has been entirely neglected.
In addition to “format shifting,” which is a well-recognized use case, and game preservation, which is a huge and under-recognized public interest in emulator development, emulators are also used for the development of homebrew software. E.g., there’s a port of Moonlight for the Switch, which lets you play Steam games streamed from a PC using your Switch, letting it serve many of the purposes of a Steam Deck. That’s huge! It would be way less practical to develop this kind of software if you could only test on real hardware. Testing on real hardware is also essential, of course, but testing on an emulator is vastly faster for rapid iteration.