Guys like Knapp were studs when they were younger (genetics/personality/take your pick) and with now decades of miles, training, and experience, they are only tougher.
I used to work with a guy who literally grew up on a golf course - his dad was the club pro. Watching my colleague play golf, effortlessly scoring low 70's while joking around and getting drunk, while I hacked away to yet another 100+ with 6 lost balls, I am reminded of guys like Dale Knapp.