I've heard the saying used to go "Jack of all trades, Master of one" instead of none.
I like they way it used to sound because it implies we should know as much as we can about everything that effects us.
It especially rings true now that w have to be our own doctors, nutritionists, farmer etc. while still trying figure out what we are actually good at, just to have a decent life.

We probably should never have lost all these skills to begin with, goes to show how much trust in the system prior generations had.