I wonder if search has become a commodity, and the reason why Google dominates isn't because of its search engine, it's because of its brand name. Search actually seems a lot like the food industry in that you can't really judge the quality of the product beyond a certain level, yet you care deeply about that quality. Those industries usually tend to become branding plays, not technology plays.
Google's brand does influence its search results. I recall the MSN Live team put the Google logo above their results and people automatically perceived them as more relevant even though the results had not changed.
