Google's original infrastructure was their main advantage, this is quickly being eroded. Ten years down the rode its not unreasonable to think that the costs to join the search business as a new competitor have gone way down.
I suspect that my increasing dissatisfaction with Google as a search engine may be a byproduct of the arms race against spammers; maybe it doesn't easily find good niche content the way I remember it doing 10 years ago because the signals of 10 years ago are too easily gamed. If that's true, then no new search engine is ever going to be as impressive as Google was when it first arrived. Similar to how no new antibiotic is going to be as impressive as penicillin originally was. The pathogenic elements have evolved too much resistance to permit the same "miracle product" experience again.