It's not even that much. You'll have to develop a taste for reading. This happens gradually as you read. Currently, the JoS alone comprises several thousand pages and is still expanding.
Reading used to be a tedious and uninteresting task for me as well, before I found the JoS, I had never read an entire book in my life out of my free will (I read a few in school), but I eventually realized that knowledge is essential for personal growth in all aspects of life. So I forced myself to read, even though it was difficult at first. It's important to push yourself out of your comfort zone to achieve any kind of progress.
Precisely, that's a good point. Reading a book doesn't only offer knowledge from the content, but it also stimulates various parts of the brain.