One of the reason is to keep on trying until actually win huge amount from the site therefore giving up gambling is not an easy thing to do. People have been struggling alot to get out of their addiction however sometimes thing like that just doesnt work at all, there are alot of ways however the most effective is to not have anything to gamble
Win or lose, people will still gamble if it already became their daily habit. Even if they got nothing, they will find a way to get the money to be able to gamble again. They can quit gambling if they found another things that more interesting than gambling itself. But it needs time for sure.