I would love that, and think it's a great model (basically "you don't have to pay us if/while you aren't making money from this"), but as far as I understand it

I would love that, and think it's a great model (basically "you don't have to pay us if/while you aren't making money from this"), but as far as I understand it, it's hard to enforce. Amazon can just make a subsidiary that makes less than that amount (or no money at all) and skirt that requirement.