While not explicit in the parent post, I think his major point was about a leader in a mature technology field not often being replaced.<p>Google supplanted Altavista largely because they made huge strides in a rather new field. While it's definitely possible, it's a little hard to image someone coming along with a web search that's impressive enough to supplant Google. It's more likely that "search" would evolve into something not entirely comparable to today's search, and replace them.