Some jocks have the brains to use that discipline they learned in order to be successful in life. For others, they were just sheep and it wasn’t really “discipline”. For those in the first group, they likely would have had success whether they were in sports or not. For those in the second group, the discipline and hard work they did possibly helped them pull themselves together and developed a work ethic. Work ethic is always useful.

He gets his crazy ideas because that’s what coaches and other jocks tell one another. It’s got some real life examples in the pros/college, but I wouldn’t say it is accurate as a whole. For top athletes maybe, but there are tons of teams full of crappy/average jocks where their “discipline” isn’t anything special.