Where did you get that from ?
The media bias seems to be to put the focus on the younger ones because they usually make 'hip' stuff. But when it comes to building solid businesses the older crowd is definitely not to be underestimated.
All founders of start-ups eventually become 40+, they have more experience than the younger generation and they're bound to do it again.
Unless their original start-up became a regular business and they have to keep running it. Decades fly by like that...
Though I wouldn't really classify rock or mountain climbing as a profession, the really good ones tend to peak around their 40s.
The books I've read on the subject indicate that though the peak physical capacity lies in the mid to late twenties, there are many other factor at play that make climbers better as they age (up to a reasonable age limit).
Experience, more long-term planning, increased ability to endure pain, etc give older climbers (30-45) a much higher chance to complete or survive a climb than their younger counterparts. The same appears to hold to true for other expeditions (long-term sailing, arctic/desert fun, etc). Football and basketball are not the be-all-and-end-all of sports.