gnobbler
I think you are saying that you'll create a product, charge $10/wk to customers and, through volume, give the tutor approx. $100/hr. Fair enough, but I think you're overestimating how well tutoring scales - which is not well at all.
If I'm a tutor, and I want to break even with my in-person rate, I need to satisfy the needs of 10x the people. That's A LOT of psets. If they have the same problems, i.e. they're in the same class, then they won't need separate accounts because they'll share screens. If they don't care about watching others, they'll watch YouTube. If you allow a large class to interrupt to ask questions, this will have to be managed carefully so the session doesn't grind to a halt after 2 questions.
I strongly suspect people will unsub after 1 session because they paid $10 to watch another guy get tutoring. Then again, I'm from the US, so maybe that's just here.