But that's one of the things that pushed us ahead, extelligence, the ability for one person to symbolically describe knowledge and pass it on to other people who may be thousands of miles away, writing was the key that unlocked humanity in many ways.
Edit: To clarify, it meant that everyone didn't have to know how to do it, we could have specialists in various things.
I suppose, as the population of the planet gets larger, the number of people who don't know how to do something will grow larger, I think that's more maths than anything else, I'll admit, I don't know how to train a horse (ironically enough, I do know how to ride one, damn parents and their riding lessons), but then, I do know how to play a guitar, I do know how to program a computer, I do know how to normalise a database, if I wanted to learn how to train a horse, I could get a book on it, we learn skills appropriate to our environment I suppose.
I think intelligence is not so much what a single person knows, at least, not in this sense, it is the fact that we devised a method of teaching that didn't even require the teacher present. Same with our physique, we devised a method of prevention of attack, by building larger and larger habitations, that meant we didn't need all that muscle and stamina any more, we lost the muscles because we advanced beyond them, I don't really see that as some kind of failing as this scientist does.