The house knows where the money is, it is in the pockets of the gamblers. If a person just asked the question of I wonder where they got the money to build such a Grand Casino, then they would not walk in. But the Gambler can't, and the gambler that likes to drink will never walk away from a free drink.
That's exactly how it works, I guess if you can't stand the heat, stay away from the kitchen! But some still do, and complain of heat.
I understand fun gambling, and that by the rich. What I don't understand is that poor guy using his last life saving for a stake hoping to hit that jackpot with a one to billion chance of it happening. It's crazy and surreal.