that's correct, gambling as a source of income is not an easy thing to do, in fact it is hard to an extreme, way more stressfull than having a job or doing other things
when you understand how it works it's clear that it's not a scam
most of the things can be understood with math
the main thing is that most lack the emotional control to be able to be realiably profitable from gambling
I doubt that learning how to control ones emotions can actually make you profit from gambling. Gamble is entirely based on luck, learning how to control your emotions only helps you make good responsible decisions so you don't fall into addiction or make irresponsible decisions because of frustration. That is why we don't have anyone who can boldly say he's a gambling expert the loses alway comes around and if you try chasing profit at all cost you'll only end up losing more than you can imagine, its a simple rule that's constant in gambling. Most people lack the ability to manage their financial risks and know how much should be spent on gamble.
Most gamblers are seen chasing profits in gambling. You cannot handle it with emotions. Here people associate their emotions with their psychological standards. By learning to control emotions, you can prevent yourself from losing more in gambling. Why should you blame only luck? You may argue that God has determined it. You can guide your fate with your own conscience and consideration. You will not find it logical to blame your own luck unnecessarily. Gamblers who determine their time to participate in gambling certainly do not carry an empty wallet. Most of them aim to make a profit. The desire to get entertainment may be very few and most of them lose their money in gambling.