The barrier to entry for someone like DDG is actually quite low I think - just have a look at how their traffic is growing (https://duckduckgo.com/traffic.html) and they're making a profit while doing it (http://fortune.com/2015/10/09/duckduckgo-profitable/). DDG has proven that you can make a growing, profitable business in search that provides decent results without needing a million AI engineers mining the search data. I don't know what Bing search is like profitability-wise, but I am sure it is doing OK.
I'd be keen to hear why you think that switching to another search engine is ridiculous? I cant think of any reasons why?
I have no data, but I reckon that most users wouldn't even notice/realise if they were using another search engine (of course, the HN readership would notice immediately - we're not representative) , and I also reckon that of those that do about half of those would only realise because the look & feel is mildly different! :-) Based on my experience I really dont think they'd notice due to the quality of the results.
But hey, I guess there are people who have niche queries they'll pull out to prove why DDG/Bing is inferior to Google. I guess some people dont remember what it was like before Google! The results from competitors are good IME.