There's search engines other than Google and there's very, very minimal barriers to using a different search engine; literally just type in Bing.com instead of Google.com. Hell, if you're on MS Windows which has a similar monopoly on desktop devices, Bing will be shoved in your face over, over and over again and using Google actually requires more effort...

Most of them use Bing's indexes on the backend and some competition does not mean that Google doesn't have monopoly power over the market. Firefox exists but Chrome still has a much larger share of the market.