The payouts are neither "subsidizing" nor "for no apparent reason". Do you think the Mozilla–Yahoo deal was also an act of charity? It's baffling that people think that the arrangement between Mozilla and Google is unique. Google is paying royalties to Mozilla for driving attention to Google properties, just like they do with their other partners who aren't named "Mozilla".

And it worked amazingly well given that they've received over $3 billion from Google. Had they then used that money to plan for the gift horse dying it would have worked out for decades more. But the people overseeing it wanted to build an empire rather than a sustainable foundation.