Page Rank is not rocket science. Sooner or latter someone else would have come to the same conclusion (using incoming links to asses popularity).

I don't doubt that Larry Page is a talented man, but he was in the good place in the good moment. Now Google is in a dominant position and there's no place for any competition, but if Google never existed, we would have some other company doing similar things as Google. Maybe they would have appeared one year later.