I think that if you’re looking for a difference between the voracious readers and the one-book-a-year readers, the answer might be that the voracious readers are better at using small chunks of time to read.
E.g., I read while I’m peeing. I can finish a page with each potty stop. I read while I’m stirring pasta. I read while I’m stuck in a line. I read while I’m sitting in the audience waiting for the play or concert to start. I read during the commercials of the football games (and during the boring moments of the game)!
My husband, OTOH, reads only when he has the entire afternoon free for reading. Of course, this means that he only reads a few times a year because he only has a few times a year when he has an entire afternoon free for reading! And when he does have that free afternoon, he usually falls asleep after the first page!
My older daughter reads several novels and books a week, and she does it in small chunks. She even reads when she drives (YIKES!)–mainly during those big traffic jams.
The other difference, I think, is that voracious readers are willing to sit quietly and read rather than chatting with pals. At work, there are several of us who read. Instead of sitting with co-workers during breaks and lunch, we spread ourselves around the cafeteria and sit ALONE, with our books propped open in front of us while we eat. I personally love going out to eat ALONE with a book! (I’m not alone when I have a book.)
I agree with the posters who say that non-readers sometimes have problems reading. I think that for some people, they can’t see the print because they either need glasses, or their glasses are poorly-adjusted for their vision.
I think that some non-readers just don’t find books entertaining. They would rather pursue some other recreational activity, e.g., sports, gardening, needlework (it’s hard to read while you’re working with a needle!), travelling, etc.
And sadly, I think that some Christians are afraid to read. Almost every book has some hint of “sin” in it, and I think some Christians are so afraid that they might expose themselves to “sin” that they just avoid all fiction entirely, and much non-fiction also. And they don’t want to pay money to companies like Barnes and Noble that sell objectionable material. etc. IMO, Christians can sometimes go too far in trying to avoid contamination by “the world.”