But why? You can develop grit by doing things that really suck, but ultimately get you somewhere you want to go, or that leads to some sort of innovation down the line. But to force people to do things that are completely unrelated to what they want to do in life, just for the sake of doing it, is a huge waste of time.

You gain grit by doing things that need to be done, hopefully in pursuit of some greater goal (more than likely, just getting paid). Not by for-the-hell-of-it forced work. That just turns you off everything.