There's a barrier to entry in that users have been trained by Google, specifically, they've run many searches with Google and over time the feedback of hit / mi

There's a barrier to entry in that users have been trained by Google, specifically, they've run many searches with Google and over time the feedback of hit / miss has trained them to write queries that produce useful results on Google. Anyone trying to implement search then either has to be competitive with Google at handling Google-friendly queries, which is probably impossible, or somehow train users. Thus, offering Bing searches as "good enough" and free to many companies makes a lot of sense. It would be interesting to see if people adjust how they search on Google vs. Bing, even if unconsciously.