One thing is missing from the OP's list: the risk of bankruptcy. No matter how many years you've been a pro making a living from it, there's no guarantee that you won't go bankrupt. You wouldn't be the first.
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.
Yes, there are, but they are gamblers who play skill games, such as poker or sports betting. The thing is, they also diversify, and they open YouTube channels, do coaching, or other activities because they know full well that gambling income is unstable and it is better to diversify sources and income for the future.