A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyse a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
"A human being should be mediocre at everything" Great advice there.
An average human to have an average life must know how to cook food, do arithmetic, read a book, write a letter, use a computer, learn a trade. Even living a primitive life, a human to survive needs to know and do more than any other animal. This is why we have our own enormous and very energy-intensive brains and not a shared hive mind. Being average is what we excel at as a species.