I do not believe in anything called professional gamblers. I see it has something that can be deceiving because there are rich people that can go broke at anything. Gambling can be one of the reasons if you solely depend on it.
Even on the gambling site terms of service, it is highly advised that people should gamble just for fun.
Yeah, I actually wanted to do that but most times people hardly trust other site to click on them, I am number one example that hardly click on external like to read through that site, and of course I could had quoted as you said but skip me.
However, I think all these are just belief and people who so much believed on something like professional gambling could like face this, but usually there are people who are losing their wealth just to gamble and if they don't apply knowledge or responsible gambling they could end up becoming broke or even penurious.