Affiliates being a standard or not has nothing to do with it, anyhody that takes money out of the deposits will accellerate the process, and affiliates took a substantial portion.
Typically if you deposit $100 a large fraction of that is immediately paid out to the affiliate. You then enter the game and if the total rake on your account ends up being smaller than what is left in your account after the affiliate has been paid then you were a net loss to the company.
Without an affiliate that would be much harder to achieve.
That said, I believe that the players are stupid enough to play until they are bust so that's mostly theoretical, so I agree that they were quite possibly sustainable but it would need some inside figures to be sure.