On the other side of that, it kind of makes more sense (to me) to buy music and rent (subscribe to) books because music is usually listened to repeatedly while books are usually read once and then not again (or at least not for a long time after the first time).
On the other hand, you will almost always want access to an enormous music library (few $ per month), but might not always need a new book. With used paperbacks only a few bucks each, you can collect (or cycle through) a lot of books for $120/year.
True. But we're not talking about used paperbacks anymore more than we're talking about used CDs. Digital copies of books are not discounted once they're "used" so you aren't going to collect as many ebooks for $120/year. It really just depends on the usage patterns. My kids could probably put a $10/month book service out of business. I would probably be their best customer with like 1 book a quarter. :)
