Occasionally, a jaded game developer gets fed up with harsh industry practices and decides to strike out on their own, starting their own game company to make their own games. This usually involves moving to a cheaper apartment and eating ramen for awhile.
And occasionally, I'd imagine a jaded university researcher gets fed up with stuffy academic bureaucracy and decides to strike out on their own, doing research as a commercial venture. This also involves ramen, unless they manage to secure a grant first.
If a teacher decides they've had enough of the system, though, there's not much they can really do. Tutoring, maybe, but it's not really the same. I suppose it's because academic programs are accredited; you could start your own university, but it takes millions of dollars, and there's no easy way to do it "on the cheap" that I can tell.
Not that I'm looking to do any of this, mind you. It's just one of those differences I noticed the other day.