I don't think they care much. Baidu works, and if they are dissatisfied there is Bing. Yet Baidu is the market leader there. Why would they switch to Google?
Why did I care when I discovered Infoseek, Excite, Open Directory Project, Dogpile (I'm fuzzy on the exact order) and eventually Google?
Do you remember your feeling when playing with a new search engine?
Differences in access to information are real and quickly felt.
(disclaimer: ex-googler. In words Google itself likes to use, because long-tail search matters. Also I should mention I now default to DuckDuckGo, on privacy grounds, but it's not a step up just "surprisingly not bad", I frequently repeat a search in Google and get more results)