Real-time Market Hypothesis - how real-time phenomenon will kill online retailing as we know it today!!

What do you think are the real reasons behind the success of online retailing?
I mean why would people willingly agree to wait for a week to get their favourite book from  Amazon and Rediff when they can buy it today from a bookstore. Agreed, it works out slightly cheaper and you don't have to take the pain of driving down to your neighborhood book store. But is that all... that makes you purchase things online?...I doubt it...I think our ability to delay gratification plays a much more important role here than what we have been giving it credit for. If you are in your late 20s or early 30s, you have spent quite a bit of time in pre-internet era and may not even realize that you are practicing "delayed gratification"; it's part of your personality, deeply ingrained in your brain by your parents; but if you belong to gen-Y, you probably can't imagine a life without instant messaging, twitter, digg etc. You'd refuse to believe that just a few years back people had to wait for weeks to receive their snail mails and didn't make them kill themselves!! The truth is - for gen-Y, the real-time phenomenon is just a logical extension to their email and social networks and soon there'll be more number of gen-Y in this world than baby boomers. 

On a social networking website, do you ever bother checking your friends old status messages..I doubt if you just care 'bout their current messages...that's what matters...a recent research revealed that the probability of a tweet getting retweeted drops dramatically after just 10 seconds from the time when a message is tweeted. What does it tell us about people, perhaps that they just care about the tweets they get in real-time...