The only thing that can change this are new players. A string of uninteresting search attempts and lackluster competition have convinced people that it's impossible to stop Google's ascent.
Google may have a network effect on ads, but the switching costs for the search app itself are small. Easier than switching free email providers. It's just another content site, and users are willing to try new search engines. There just haven't been any interesting new ones to try in a long time.
I was hopeful that Wikia would launch something interesting and break the n-game losing streak of the upstarts, but sadly it was another shallow effort.
I'm rooting for Cuill next. They have a very credible team. Anna built the current version of Google, and now she's working on the next gen. If they launch something interesting in any dimension, they'll show the market that you don't need a million servers and half of the phd's in the field to build a search app. It takes 20 people and $5M of hardware...if you know what you're doing.