Your idea about casinos is not entirely correct. Many casinos consider the interests of gamblers. If casinos only thought about their own profits they would not have so many users/gamblers. Gamblers are not prepared to lose every time just for fun. They want to make money, even if it is small amounts along with entertainment. Patient gamblers can achieve their goals.
Casinos never do anything for free. However, the competition among casinos is so high that they are forced to offer better and better conditions for their users. Yes, there is an opinion among the players that the more you play, the higher the chance of winning large sums. Therefore, many players continue to play and play as much as possible.