Once again, you are not the customer, you are the product. Search engine customers (advertisers) gravitate to the largest player because it provides a larger inventory of users/searches to select from. Search advertising is a winner-takes-all market and it would take a huge shift in inventory to change this momentum. Once it starts shifting it is hard to stop and the changing economic factors make it easier for the insurgent to capitalize on whatever mis-steps the incumbent made, but there is a lot of inertia to overcome to get this ball rolling.

A far more likely scenario for a major change in this sector would be for social search to eclipse the crawl it and rank it model that is currently dominant.

Hm, I wonder whether the way to take on Google would-be to remove that setting. Build an engine and offer the phone companies a part of the advertising revenues if they hard-code that engine on their phones.

Problems there would be a) to beat Microsoft and Google at that game, and b) it would turn search into a low-margin commodity. Both make it hare to turn a profit.