The public image of these 'whales' is the immensely rich person who visits a casino a few weekends per year and casually loses a hundred million that they won't miss, but a lot of the 'whales' are people like the ones in the article, middle class people who lose hundreds of thousands of dollars while desperately trying, and ultimately failing, to stop their addiction from ruining their lives. As far as I could tell, across different gambling businesses, the focus is on 'whales' - chronic gamblers who spend as much as they can or more on gambling. I really enjoyed the interview (interesting tech, really smart people) and I've placed a few bets along with friends before in the past without ill effect, so I did some quick checking about how gambling businesses make money.
I was recruited by a sports gambling company and went as far as interviewing with them.
'The company has said in previous court filings that only a fraction of the game's players actually spend money.'