Dude, I assure you, no one will ever beat eBay at being eBay ... their network effects are in a different stratosphere.
But that doesn't mean it's not a good time to start a sweet company that could someday eat eBay's lunch from a different angle ;)
Exchanges are much more primitive than search before Google. I'll hold you to that assertion... :)
I 100% agree with you. But Google approached search in a different way than the rest, that turned out to be more effective. Likewise, I think there's got to be a different way to think about selling that can really undermine the traditional model... go forth, conquer!