I agree, even if is true that most of the time those that put the most effort into their hobbies are the ones that obtain the most benefits out of them, and they may even make money with something that was just a hobby, this does not really apply to gambling, and this is because in most of the games offered by the casinos, it does not matter how hard you may try, you have no chance to improve your results as your luck controls everything, and in that case, it is better to simply give up for those that have lost a lot of money already.
I had the same thought. No matter how hard we try we will never win against the casino because their system will never let us win and their basic odds are against the player winning. So for gamblers who have thoughts that they can make money from gambling, they will tend to continue betting even after they suffer a big loss because what is in their heads, is the opportunity to recover their loss but, what will actually happen is a way for them to get worse.
I think it's just people who have thoughts that gambling is just a hobby to have fun with what they can afford to lose, are those who can stop betting when the loss comes.