O.K. so he's not saying everything, of course, because he want's you to buy the book.
But I get the idea and must admit that he's got a point. Champions are made and not bred because of opportunities. Lots of potentials getting together in the same place and pushing each other whatever the sport because that's what everyone in the area does at that time. Fashion, popularity. Take the karate perspective. Wolverhampton YMCA in the 70's? Liverpool red triangle? The clubs were there, the fashion at that time was the Bruce Lee phenomena, loads of fit young men wanting to learn to fight.
"The year in which I began my training was during British karate's heyday. In 1973, Britain defeated Japan in the final of the second world championships in Long Beach California and would go on to dominate the world championships throughout the 1980's. While Britain was the foremost team in international karate competitions, a club called the Wolverhampton YMCA was, for a period, the top club in Britain. Therefore, by most objective reckoning, it was during that time, one of the finest karate clubs in the world.
The YMCA was, in many ways a freak of nature, it was a series of coincidences which brought together outstanding fighters who just so happened to want to learn the art of karate at around the same place and at the same time. Their collective attitude could be summoned up as: go anywhere, fight any style, under any rules - and use whatever referees you like. The team won so many tournaments that it would be impossible to record them all but amongst the YMCA's greatest achievements were two British All-styles titles, five national Wado Ryu championships and in 1976 a national Shotokan championship - the only team in the history of British karate,not to practise that style to do so."
Ralph Robb
Memoirs of a Karate Fighter.
Clusters of excellence suggest opportunity and likemindedness rather than genes.