hi,
OP: That source is very idealistic, it is based on what is expected of certain players, but in practical reality things are not as they are mentioned.
Of the things that the source says, it is important to highlight that a professional player is the one who pays his bills. He is the only thing that matters, at least in poker.
If you can pay and make winnings your main income, that makes you a professional player, who after that can easily go through the other "characteristics" that define a player, according to the position of the OP, Casual Social Gamblers, Serious Social Gamblers, Relief and Escape Gamblers, Conservative Gamblers, Personality Gamblers, Compulsive Gamblers.
For someone who manages to have an acceptable bankroll management and have an average monthly income can easily live on bets, this that there are few professional players is not so true if we compare it with other professions.
There are professional players who lose indigent amounts of money, there are professional players who are compulsive, uncontrolled, that "idealistic" concept of control is a fallacy, unless you only play face-to-face bingo.
At least in poker, professional players go through phases of downswing and go through phases of depression, change of style of play, etc.
A professional player really deals with all the evils that you name, he suffers from them like any other person, there are professional players who deal with the anxiety of betting, etc.
Finally, I would say that at least in poker there are 4 types of players:
Professional.
Semi-professional.
recreational.
Fish.
And to specifically answer the OP, sometimes I'm a winning player, sometimes I'm a losing player.