The meme is real, but that doesn't mean that Mozilla is suddenly bankrupt. I can't speak to Mozilla specifically, but there are non-profits like Wikipedia that set up stores of money equal to at least a full year of operating expenses, so that they can work to pivot in the face of exactly this kind of eventuality.
Google will appeal the ruling, which will drag out the measures for a while still, and no one knows yet whether they'll actually be forced to stop paying Mozilla. Presumably, Mozilla will mention in court that this is a real fucking problem and would actually weaken Google's competition. But the concern is still there, yeah.