Brave supports manifest V2 because the Chromium upstream hasn't removed it for enterprise use yet. As soon as that changes, Brave does not have a plan to continue maintaining V2. What you call Google payola is really the independence that allows Mozilla to develop a browser engine that isn't being actively crippled by Google's initiatives. That's the important piece. Brave is not a sustainable play because they have no way to fund a forked version of the chromium browser engine when Google inevitably cripples it to invade our privacy even further.