Only a few of those people earn money from gambling because they are very lucky and because of their exceptional luck they win the house edge of the casinos. Most of the ones who look to make money from gambling end up getting addicted to it, and instead of making money they lose money.

I know we can't consider gambling only as fun activity as it can be a source of income for  very lucky people but if we go deep in it then we can understand that those lucky fellows are less than 1% of the gamblers.

That's why I believe if someone wants to start gambling for fun then it's okay but if someone gets into it for money part then they might get discouraged if their luck isn't exceptionally good. I believe that one should look for the entertainment when they start gambling and if they're lucky then they might get some money as well.