I suspect the main reason for Google's stranglehold is that it's usually set up as the default search engine for many web browsers (both for desktop and mobile)

I suspect the main reason for Google's stranglehold is that it's usually set up as the default search engine for many web browsers (both for desktop and mobile) and the vast majority of users don't change that. In spite of its good growth rate, DDG will have to change tack if it wants to make the leap to the next stage. *FYI, DDG is my default search engine.