Reading requires active effort. Until we develop "I know kung fu" [1] technology, any substitutes for books will likely also require more effort than just an initial purchase.
It hasn't really slowed down my bookbuying any, but it has sped up my bookreading, which is better anyway. I generally read in the morning before work, either on the bus (if I'm commuting) or in the coffeeshop nearest work (wherever that happens to be at the time). Just half an hour a day gets a lot of books read during the year.
It's always handy to have a few unread books available though...