Whitehead was a gentlemen's gentleman. He had much better uses for his time and energy. He retired from his math career at about 60 and then began his philosophy career, and it was quite a productive career.
I guess you could say I "changed careers" about that stage myself. I too have waxed philosophical, but I express myself in poems.
I don't have any of his works in my private library. I'll have to visit the public one.
I can't afford to buy all the books I want, so I write some of them.