May I be frank? I suspect that, in the long run, Mozilla not getting this money will actually benefit Firefox. Sure, so exec will get pissed as they won't get 5.6 million dollars a year, and Firefox won't get some weird nobody-asked-for feature that'll be ditched some time later; but I think that they'll focus better on the browser this way. Specially because whoever is paying the dinner is the one picking the dish, and with a higher proportion of their effective income coming from donations, what users want will stop being so neglected.
Just my two cents.