I can focus quite well on an audio book if it is read by someone who knows how to make a good recording (Steven Fry for instance does some great books).
My problem is that I used to read a
Lot and quite fast too and I am particularly prone to binging things. This is why I don't like or watch regular tv, I despise waiting a week between episodes, I enjoy being able to just sit back and consume a good story until I'm satisfied. It's not about being impatient or will power as I can wait when I have to I just prefer the choice to take on as much or as little as I want, when I want.
It may have more to do with areas of interest, I would probably get bored of a book after a couple weeks if I was only getting a chapter a week, it becomes more of a chore to continue reading rather than a piece of entertainment to enjoy spending time with, and at that pace whatever peaked my curiosity and interest in a particular book might soon get replaced with a different interest after a few weeks.
Things come and go in cycles with me like a few weeks ago I started watching "from" which really got me wanting more 'mystery' stuff, depending on what happens in the next few weeks I may end up wanting something lighter and comedic or perhaps darker horror maybe I might suddenly get an itch for geeky sci-fi space opera stuff.
The last time this happened with a book was with "the lies of locke lamora"
Which is another really good book that I was getting into but could only read a little at a time, then I saw something that pulled my interest in a different direction and I never finished it, still haven't been able to get back into that one yet which I really should.