People usually don’t respond well with threats they don’t perceive as harmful, or can’t perceive physically at all. Targeted ads and privacy in general is abstract to many people, and the only time they’ll start responding is if their emails or social medias get hacked due to their infos being sold on the dark web or something like that.
Firefox’s user base is apparently been dwindling for a long time now, so the possibility of this browser shutting down due to not having enough funds is getting higher and higher each year. At least, that’s how I interpret it.