The truth is that browsers are a very complicated, very quickly moving, and very security sensitive piece of software. They spent all that money on Firefox rather than saving it because if they didn't Firefox would have fallen behind Chrome and Safari and it wouldn't be worth using today.
It makes no good goddamned sense that money that was given in order to be featured in a web browser cannot be spent primarily on that web browser, and can only be spent on anything except that web browser.
I know they cut back a little but maybe they’ve sobered up since? Haven’t had the heart to look again.