I got curious and validated your source [1], to pull the exact quote:

"The proportion of Connecticut gambling revenue from the 1.8% of people with gambling problems ranges from 12.4% for lottery products to 51.0% for sports betting, and is 21.5% for all legalized gambling."

Without going into details, I do have some ability to check if these numbers actually "make sense" against real operator data. Will try to sense-check if the data I have access to, roughly aligns with this or not.

- the "1.8% of people" being problem gamblers does seem roughly correct, per my own experience

- but those same 1.8% being responsible for 51% of sportsbook revenue, does not align with my intuition (which could be wrong! hence why I want to check further...)

- it is absolutely true that sportsbooks have whales/VIPs/whatever-you-call-them, and the general business model is indeed one of those shapes where <10% of the customers account for >50% of the revenue (using very round imprecise numbers), but I still don't think you can attribute 51% to purely the "problem gamblers" (unless you're using a non-standard definition of problem-gambler maybe?)