While some whales are definitely high-earning professionals who can afford it, not all of them are. I'd be curious to see research on what the split is. It's hard not to notice, however, that gacha games heavily rely on the same kind of skinner-box gambling systems as actual gambling uses with little of the regulation around payouts, transparency, and age restrictions. People who have problems with gambling, report having problems with gacha as well. See also this video of some testimonials: https://www.youtube.com/watch?v=7S-DGTBZU14