I can't help but think that both of those issues are eminently solvable. In the case of teachers, focus on making a product for the teachers, then charge them either a flat fee or a percentage, ala kickstarter or patreon.

As for the nobody finishes, that is even easier: use Beeminder[0], and if you are writting a mooc platform, integrate with it.

[0]: beeminder.com; self-control as a service; I am a very happy user, but, except for a few stickers, an unpaid shill.