Mozilla is the one who is funneling billions of dollars worth of traffic to Google.
Google's only reason for keeping Mozilla on life support is to avoid the argument of being a total and complete browser monopoly.
Firefox's global traffic market share is less than double digits [0] and is less than 5%. Google technically doesn't need traffic from Firefox and Google is roughly paying half a billion ($585M) a year for it. [1]
[0] https://gs.statcounter.com/browser-market-share
[1] https://stateof.mozilla.org/pdf/Mozilla%20Fdn%202024%20-%20A...
So, is Mozilla promoting a search engine monoculture? Yeah, "Google bad, but..."