Is it possible that studying Nobel Laureates skews these numbers? It would be extremely difficult to receive a Nobel for an achievement late in life because of the usual lag time between the achievement and the award and the fact that Nobel prizes are not awarded posthumously.
It's possible. Furthermore, the article talks about noted achievements -- the case where someone's work is recognized as particularly good.
Your best or most-creative work isn't necessarily the most-recognized.
Being better-recognized probably also correlates with having built a network of connections, understanding institutional politics, having built up social capital (favors to call in), and so on. And it wouldn't be shocking if that tends to skew stronger among older, more experienced people.
