Books can make you smart, you can borrow amazing insight from brilliant minds and this is a big advantage.
But you can't out perform a high iq individual if you have mediocre iq.
I am a realtor with an average iq, I have brilliant colleague, he has lightning fast mind with amazing ability to connect ideas and knowledge.
During our conversations I have hard time following his vast portfolio, connections and solutions.
So high iq is definitely an asset, a high iq person can literally learn on the go.
So mediocres need books and extra effort to be competitive, highly intelligent fellow don't depend on them, but if they also happen to read a lot they lead by a land mile...