Not the slots alone but the whole casino is designed to for people to lose but for the owners to earn money, we all know that not all the time people are losing, there's still some people who wins jackpot and big prizes but only small number of people who can get that and even if you think that the casino will lose from that, they still on profit.

Casinos are designed to entertain people and leveraging money to attract players giving them chance in to multiplying it but in reality, the more you play the more losses you'll have.