Our age reveres the specialist but humans are natural polymaths

The modern examples of Francis crick and Feynman are not examples of polymaths. Their achievement came from absolute dedication (most of their life) to their field. The fact that Crick came from a physics background is irrelevant because his professional career was entirely in biology. Feynman being able to play bongos and crack safes are nice anecdotes, but he was not successful because of his hobbies. He picked these hobbies up after he became a first rate physicist

You can pursue the polymath direction if you want, but the vast majority of people who pursue this path are unremarkable in any of their works. The examples you bring suggest a deep plus broad approach: become the best at a narrow field but have a broad enough perspective in order to see connections between your expertise and other people's expertise.

The dangerous advice of not specialising (read: focusing) lead people to do these broad college degrees and then expect to somehow be able to compete with those who have specialised. They have it backwards, first you specialise so you become useful, then broaden to see the connections and collaborate