Doesn't Mozilla foundation have millions of dollars, including paid for by Google? "Linux" is better capitalized, "Wikipedia" is sort of open source, what else ranks above Mozilla?

Firefox works everywhere I point it to, for now. "Let the user modify their own software" does not cost extra.

Being beholden to Google who might decide that the risk of antitrust is lower than the price they are paying for that search box is a pretty precarious place to be in.