Books provide information only. . . As we see that people who are educated but they are not having knowledge of each and everything because only reading won't help but understanding ehat you are reading and then making a scenario or building up the concept by thinking about it will make a person gain the knowledge about the text one read.
Good books will build your imagination and provoke your thoughts on scenarios and can help you critically think.
There are people who learn with hands on training but they will always be under the ones who learn about it and make the rules and design new creations.
My dad knows about wiring and electricity but he does not know the debts or why.
And then it goes into superstition and erroneous beliefs. Like grounding and improper protection.
You need more information and knowledge that books can give.
Hence why engineers are superior than trade men.