Every time a gambler deposits BTC into a casino, it goes into their bankroll. Casinos don't feel like they're losing out even if the price drops because they have several deposit options, such as stablecoins. So, casinos still win and profit because gamblers will continue to gamble, and the casino will actually profit even more when the BTC price rises, as they have a significant bankroll. One thing we must remember is that casinos never lose, and gamblers always lose.