Almost all of the better players in leagues (at least in my area) are engineers, computer programmers and such, doctors, lawyers, high level trades people, those that travel a lot, etc, but there are no really top regional or pro players like that.
I don't know why that is, but I'm guessing those smarter and/or more educated people put time in to get better and try to learn all they can, but are missing the natural talent and time needed to get really good.
This is the same in my experience. But, it might not just be a lack of natural talent. I've seen some incredibly talented players who could certainly at least mix it with the pros over a long run of games. If these guys had the time/were inclined to practice more they would become much more consistent (more consistent than just being 80% in a league in their worst seasons) and wouldn't be have to rely on margins of error as much. The mental game would be different too - these guys play with a lot of freedom as they are 60-40 against even the best players they play against.
Having said that, its a small samples size - I've only seen a handful of league players that I think could be world class (but are happy being world class social players). Time, inclination, talent are all factors.