It is only rich people can use gambling as entertainment because for them the result of losing is only entertainment. But many people gamble with the dream of becoming rich, but when they lose, they lose their money. Gambling is difficult to lose, so there is no entertainment. I was sitting in a shop eating and next to me a man was placing bets repeatedly in gambling. I see his wallet he has lost a lot of money yet he is betting but this was not enough entertainment for me. Because I know that it is difficult to earn that money if you lose by gambling.
Entertainment is in the mindset. For instance, sport is entertaining, but hysterical fans get to cry or feel moody over a missed opportunity that led to losing a match. Over the period they'll worry about this, but months or years later they'll look back and laugh over it. However from the point of view of gamblers, their mistakes rarely allow them a time of transformation; turning it to a fun factor. It remains a lifetime sad memory for most players. Possibly entertainment has to do with an enduring memory of fun and laughter over a mistake or good deed. If a gambler doesn't have this recurring memory of constant happiness coming from his gambling experience he's not getting enough entertainment through gambling.