They don't have to. Repeatedly unearthing cow-clickers whom you can milk for $10'000 before sending them into financial ruin sounds like a much more viable business strategy to me than trying to build a portfolio of people both rich and dumb enough to sustainably cow-click.
I think you're putting wealthy folks on way too high of a pedestal. The wealthy aren't some hyper-rational, utility-maximizing robots. They're people with likes and dislikes like any other. Being a whale for a very rich person or a very rich family is a drop in the bucket in terms of their net worth. Plenty of people can keep their degeneracy to a budget.
Does the same pattern hold true for casinos? Or are the bulk of the profits coming from the poor SOBs who blow every paycheck there?
There's an increasing number of players who expect that either a) a game will take unlimited money and feed them dopamines in return, or b) they never have to pay a dime for anything because they're fully subsidized by the addicts. I have conflicted feelings about administrative regulation of this stuff, I just hate that things are this way, especially as an independent game dev.
(I'll do the hustle - my first game Pawnbarian is a chess-flavored puzzle roguelike. On mobile it's an ad-free demo with a single $7 IAP for the whole thing. Out on Steam and Android, iOS will follow soon. j4nw.com/pawnbarian)