I would liken it to other kinds of encounters. Let's take encountering people. Do you want to fall in love with someone, do you prefer to flirt with many, do you want a strong friendship, or a passing chat. Each relationship requires a different kind of activity, and a different kind of concentration. Or, take visiting different countries. You get something from being a day somewhere, something else by being a month, and something different from living a year.
Similarly, you can get the entire human experience from a single book, if the book is good enough and you read it carefully enough. I usually prefer total focus when reading a book, and I read it very slowly. Sadly, it means I don't read as much as other people, but I think it's better like that.
Sometimes, when there is a problem I'm thinking about, I might raid my library and look for whatever writing I can find on that particular topic.
Jumping between many books seems to me like having many meaningless friendships, instead of a few great ones.Still, you do want to meet different kinds of people, so it does help to read different books, but you are in a different relationship in that case.
There used to be people who never traveled outside of their village, and still, like Jules Verne and Agatha Christie, managed to get the most out of their surroundings.