There are effectively only two competitive search engines in the U.S. and European markets today. In those markets, Bing is the only market pressure keeping Google honest.
There are only three major worldwide English language indexes—Google, Bing and Yandex. For all the praise DDG gets here, it couldn't exist without Bing.
https://www.quora.com/How-is-the-Bing-API-used-by-DuckDuckGo
There are effectively only two competitive search engines in the U.S. and European markets today. In those markets, Bing is the only market pressure keeping Google honest.