It's the time investment. I read at blinding speed. Seriously, I can read a novel in half a day. Listening to something is so slow it's aggravating. I can't easily do something else at the same time, and I get bored.

Yeah, I get that. I used to feel the same way--it frustrated me that I couldn't affect the speed of reading. But then I started to think of audiobooks as a different medium entirely from books. It's not really the same thing as reading at all, and I get other things out of it than I do reading a book.

But yeah, I get that it's not for everyone, especially if you can't do other things at the same time! I usually listen while washing the dishes or walking to work, when I couldn't read a book anyway. (Well, okay, I have been known to walk around outside with my nose in a book, but it's certainly not ideal. *g*)