I know both Greg Whitely and Hunter Kemper. I was the collegiate national tri champ and a professional tri-geek after college... I beat Hunter at 92' worlds in Muskoka Ontario....My last time ever beating him!
the article you reference is so off in comparing the two of these.
1st: Hunter was a triathlete first. He was an ironkid at like 8 years old and always knew how to run off the bike. he just wasn't fast at it until college. he only got serious about running in college.
2nd whitely was never a triathlete. by the time he turned pro as a tri guy, he was well out of his prime prime running shape. I guess he could muster a 15:00 open race while he was tri training. We trained in Eugene when he was starting out as a pro tri guy.
The true difference is confidence in a triathlon. Hunter knew swimming and biking and simply added the last piece. his confidence was always growing in the sport and that kept him running fast off the bike, he was always in the hunt.
Greg, never got to build his confidence in tris. his confidence was always going down, because his swim was off and his bike was fine. if he made it to the run, he was dejected and down.
if whitely got off the bke with the leaders, trust me, he would have crushed it. he was never in that position to benefit from confidence and motivation.
Both great runners coming at running in triathlons from completely different psychological angles.... which dictate the physical potential