We don't have to be experts in everything, but we do need to know enough about everything to avoid getting taken. A CEO must know how everything works so she can pull in the reigns on her VP of Digital when he's building something that's way too expensive, unnecessary, or hard to pivot from.
A homeowner must know how the furnace works, where the fusebox is, and how much it costs to fix the roof.
Being conversant in many things because we've done the research that enables meaningful participation, prevents us from paying top dollar, whether in time or cash, for someone to solve our blind spot.
Blind spots are dangerous. The bottom line is, 'don't know' = huge costs.