I gotta imagine much of them weren't actually successful.

You're right. Any individual person going in for these scams is almost guaranteed to lose their lunch money. But from Etsy's perspective (and I assume Imgur's), they only need a tiny fraction of their sellers to get the jackpot in order to keep the money train rolling. If they can get a single dollar a month out of 20% of their users, that's still a baby dragon's worth of a horde every 30 days. And I'm sure they have other fees and hedges to ensure that even if you never make a penny in sales, Etsy still comes out ahead on you.