Why we expect more traffic from only Google?

I believe most of the websites are expecting traffic only from Google. I don't know, why? Still I am finding good answer from online through only Google.

I don't know how to find the search results other than Google. I knew about Yahoo and Bing search engines but still I could not believe all the leading search engines. At the same time, I believe only google is the leader of search engines to make everything is possible for us.

Am I right?