Not sure how true that is. Non profits definitely rely on donations as their sole income, and are incentivized to take actions to maximize donations, but the difference is that (ideally) they can't really line their own pockets with the income that comes in. So the only reason they would maximize their income is to put more money into the things that they do.

This is not the case with Brave. The browser is a front, or a channel, for their token and ad network. They only need to keep the browser part of it functional enough to keep traffic. They have no real incentive to improve the browser beyond that point, especially if other competitors stagnate and the money keeps coming in.