If you're in sport, you know that highly performant bodies don't look like that almost ever. They're too specialized to have the physique that prioritizes aesthetics. Road cyclists with their lanky frames, powerlifters have fat over their absurdly strong cores. High level marathoners look like they might blow over in a stiff wind.
The most interesting thing about the article to me was the mention of kinesthetic skill. This is a huge differentiating factor IME in mountain biking. Some people do not have the meta visualization to understand why what they did worked or didn't, why they cleared that rock, why their weight transfer caused the front to wash out. The feedback loop doesn't exist, and they can't progress.