There's a dozen Firefox extensions that really matter, at any given time. Mozilla has never appeared to give a particular shit about any of them. Paying special attention based on popularity wouldn't be ideal, but for fuck's sake, their passive-aggressive treatment keeps burning out the developers who fuel their ecosystem, and it would take vanishingly little effort to shield their keystone plugins.
If their active neglect had ruined both uBlock and DownThemAll - I'm not sure I'd be using Firefox anymore, and I've been using Firefox since before it was called Firefox. Why the fuck would anyone normal even consider it?