Umm, the article says it's the other way around.

In order to secure the company’s position as the default general search engine for mobile and computer applications, Google allegedly entered into exclusionary agreements to guarantee that consumers would use Google search engines by default on their devices and web browsers. Under these deals, Google allegedly pays billions of dollars every year to device manufacturers like Apple, LG, Motorola and Samsung; major U.S. wireless carriers, including AT&T, T-Mobile and Verizon; and to browser developers such as Mozilla, Opera and UCWeb.

I suppose it's better to have Mozilla’s finances secured this way, it helps speed up Firefox developement. I guess that this will not last forever. Until then, Add or remove a search engine in Firefox

Regardless of the installed default search engine, you always have the option to change it.