I think that this is true. I read, on average, one book a week. I like non-fiction, and prefer history, but I'll read fiction by McMurtry, McCarthy, Kellerman and King every so often. It often surprises me how many people my age don't read. Usually they say that they don't have the time, but I think it's more that they don't have the inclination.
I wonder how many of the kids growing up in today's environment are going to be diagnosed with ADD or ADHD simply because they don't have the patience to read a book or concentrate on a single task. If that's the case, then a lot of adults are inflicted too.