At Blekko we built a search engine (crawler, extractor, ranker, fetcher, the whole stack) and let people know exactly how we rank things, for users who created an account and logged in they could turn off everything except organic results. We have been moderately successful (we were the first to use a 'masked results' option [1] to show how much better our results were than Google's in contested searches) but there isn't enough outrage about that yet to build a business yet.
Most of our business (people who pay us money) comes from folks who either want to figure out how to game Google's results, or want some organic results to create a 'search like experience' much as Google does. When you think about it with only 7% of the page dedicated to organic results that is like 2 or maybe 3 actual search results and the rest of the page is a carefully crafted advertising vehicle. Sort of like a free 'newspaper' which has one article of editorial content and the rest are all ads. You can serve that market quite effectively with a relatively small index (a couple of billion URLs).
If you look at Google's financial performance over the years you can see how this evolution has affected their bottom line. Today you see it in declining revenue per click sorts of things. It feels to me as it did when banner ads went from this massive cash cow into something less useful.
One thing is true though, the world is changing yet again.
[1] http://techcrunch.com/2011/06/21/be-the-mark-in-blekkos-3-en...