"emotional regulation" is not exactly a term I would use to describe the majority of professional poker players, although I think it is more prevalent within the better ones. Patience and discipline are probably present within anyone who manages to survive as a pro for more than a couple years, but it's not a guarantee. There's a reason the term "degen" (for degenerate) gets thrown around so much in gambling circles. I've played thousands of hours against mid/high/nosebleed stakes pros who've played many more thousands of hours of poker than I ever will, and it's always a surprise how many of them are children throwing a temper tantrum whenever they lose any hand where they were a favorite. (This includes multiple people who each have multiple WSOP bracelets.)