I think this is one of those memes that only serves to put a lot of unnecessary pressure on people. It's one of the driving reasons why we see posts here from people who believe they are too old to learn physics or that their opportunity has somehow passed them by when they are only in their early twenties.
It's important to remember that historical context doesn't apply. I've seen people compare themselves in modern times with Michael Faraday! The thing is, that the state of human knowledge has grown considerably. Most people are close to 30 or even past it when they are awarded their PhDs. Then they have to do post-doctoral work, and it's not until they are into their mid thirties or even pushing 40 until their in a position to really put a lot of effort into their own "best" ideas. The fact of the matter is that while you may be in your "prime" physically in your 20s, most modern scientists are still learning at that stage of life.