The market is open to competition, and Google is very disruptable, if somehow you think you can do a better job than they do. If another Larry and Sergey came along with a search engine that was significantly better, they'd disrupt Google just as easily as the original Larry and Sergey did to whatever was popular before them (I don't even remember.) Do they have the vast majority of the market share? Yes. But they also have plenty of competitors and there's no lock in for people searching, nor a high pain threshold for people to switch search engines. The reason Google holds such a dominant position is simply that their search results are best. If that weren't the case, I'd switch today, and so would you.