If Brave succeeds and will be allowed to operate this scheme, then network operators, ISPs, device makers, etc. will also get in line and devise similar schemes where they replace ads (even possibly Brave's) with their own, and take another piece of the pie away. The publishing ecosystem will be flooded with such parasitic entities, and the publishers will get no money at the end.
So, no, this just can't work. Brave - just like regular ad blockers - adds no value to the ecosystem, only tries to extract revenue from it. It's a parasitic scheme, which does not solve, but deepens the problem, which is the financing of online content.
And don't even get me started about how stupid even the basic concept of Brave is - that is, paying users to watch ads. This has been tried over and over in the last 15 years, and has failed every single time. It's open to abuse, does not net anything to the average and honest user, and is completely backwards anyway.
Brave's business model just can't and couldn't work even then, if it wouldn't block ads from parties it has no explicit agreement with.
Anyone who knows about brave also knows about ad blockers. So most likely they will get something from brave or the user will choose ad blockers in which they get nothing. Brave is ahead of it's time, these companies who are barely wrapping their heads around decade old ad blockers can't compute.
I understand why companies run ads on their sites, however, websites running ads have no one to blame but themselves, as a collective, as there wouldn't be a push to block ads if websites had never abused using those ads.
There is a tasteful, non-obtrusive way to display ads on websites... when you plaster the page with ads, have ads auto pop up, have ads auto play, etc. it irritates visitors to that site and almost ensures they will look for a way to block ads. This isn't a small amount of abusers either... a significant percentage of websites run obtrusive ads on their sites.