Their transaction costs have got to be sky high. Payment processors consider this high risk. So if it's any consolation, the payment processors take a significant slice of the rake.

This is why you see fantasy sports succeeding where previous "games of skill" wagering failed. Fantasy sports draws on the real event for some of the value to the player, and players will put up with a high rake. Not so much for a poker room.

Low stakes poker tournaments both live and online have juices >= 10%. See any live tournament up until maybe $500 buyins and $5+0.50 SNGs that you play online. The $1 SNGs are juiced like 25%. People still play them anyways.

Not necessarily disagreeing or agreeing with you about 10% of rake being a scam.