Increased features - products are getting better all the time, and especially for electronics, there is a chances that the latest model includes cool features that didn't exist when your old one was made.Now you can get a high-definition digital camara that is small enough to fit in your hand
Some will argue that the throwaway society has been bad for other reasons - increased trash, loss of old-school charm, ect. The "landfill crisis" has been debunked by many, such as Bjorn Lumborg in the Sceptical Enviromentalist. And if people cared about old-school charm, they wouldn't vote with their wallets for assembly-line products.