I also believe in this one, just think of this idea. Why do casinos offers much like a comfortable and even grand place and freebies like water, juice, alcohol, etc. to its players even though they are winning a lot? It is because even though players won the jockpot many times, the house earned it also as many times as the winner in a row. Where do they get those high jockpots though? Maybe if someone wins, they get doubled.
Not every casino has similar returns. Bet365 is big. like REALLY BIGG!. I know about many casinos and online sportsbooks that are barely managing. Heck even, directbet couldn't keep up with the high bitcoin fees and was probably why they closed 2 years back. They have an edge, but players these days have many options. In order to make money they need volume which not all casinos have these days.