Bill Gates: "Intelligence is not fungible."
Proverb: "Jack of all trades, master of none"
Jim Collins: "hedgehog"
Buffet and Munger: "circles of competence"
Mark Twain and Andrew Carnegie: "Put all your eggs in one basket and watch that basket extra-carefully."
I like this spirit of humility and modesty.
Given our human limitations, we can't escape focus and specialization.
However, hedgehogs shouldn't be too smug either.
With your shiny, trusty hammer, what if everything does look to you like a nail?