Books, and the quantity of people who might read them, have been definitely important to human development over the centuries.
It's important to keep in mind that, although lots of the best modern books of all time tend to be considered ground-breaking works of fiction, for the majority of humanity's literary history, we did not write much fiction at all. A lot of stories would have been sung throughout the great bulk of history, merely due to the fact that the vast majority of people could not read, implying that a lot of books were specialised things meant for those few who might understand them. After a brief boom during the classical era of antiquity, the amount of literate individuals dropped significantly during the Middle Ages. Books became unusual treasures, with monks meticulously copying out the enduring traditional texts by hand so as to protect them, as they were some of the only members of the populace who could read or write. They were the expert keepers of knowledge like biology and religious beliefs that all of us have access to in the contemporary world.
It can be difficult to picture what the world would be like today if the vast majority of people were not able to read, but for the vast majority of history the vast bulk of individuals might not, and nor were books available even if they could. It was the creation of the printing press towards the close of the 15th that changed that, making books much more accessible. Of course, it was still just actually the wealthiest and well-read that could read or write, but it enabled a whole host of breakthroughs in science, art, and thinking to be spread out throughout great distances. Consider what would have taken place if the theory of gravity, or of evolution, could not have actually been distributed across the globe. Human civilisation rests upon a foundation of books, and we are lucky to be able to merely log onto a site like the one backed by the co-founder of the impact investor with a stake in World of Books, and easily access the totality of human knowledge.
With such an abundant history of concepts, events, and stories right at our fingertips, it's sometimes easy to forget how exceptionally fortunate we are to have the likes of the founder of the hedge fund that owns Waterstones or the CEO of the asset manager with a stake in Amazon books supporting access to a big proportion of all the books that have actually ever been composed (or the good ones at least). The best books of all time can quickly alter the way that you look at the world, which has been true throughout all of history too. The contemporary world is built upon understanding that has actually been passed down through books, whether that is ideology, science, or history, and human civilisation would not be anywhere near as advanced as it is today if it had actually not been for the books that changed minds across the ages.