John Fenn, the discoverer of electrospray ionization (ESI), the key element in modern mass spectrometry, did his Nobel Prize winning work in his 60's, at the end of his career. He was semi-retired, a forced retirement. His work was based on the understanding of the "Taylor Cone" a paper published by Geoffrey Taylor when he was 78 in 1964.
Fenn's work on ESI took place after he had reached mandatory retirement ,(70) age at Yale. (He and Yale spent years suing each other over the rights to the ESI patent. Fenn lost the lawsuit.)
He was 85 when he was awarded the prize.
I think the myth that people can only produce great science when they are young, is that when young people do great science that rises to prominence, they can be distracted by their fame and find it hard to continue their work. Richard Feynman complained about being awarded the Nobel Prize without his consent, because it distracted him.
Obscurity can be a good thing for doing good work. Experience, and failure, are also benefits that can lead to good work.