alt Hacker NewsA decent chunk of the users who bothered installing an adblock would also be bothered enough to install a FF fork with adblock, so I doubt the revenue increase would be much.
As for calling it "off-mission": yes, what's even the point of FF if that's the route it goes on?
Do any of these forks have the ability to sync, either with Firefox or something self hosted? Or are they all just basically reskins with a single toggle added or such?