Any form of advertising will eventually corrupt the platforms that rely on it to exist. I guess any platform which supports advertising will eventually turn into an advertising platform. Brave essentially is an advertising platform through their brave rewards (however complicated they make this relationship out to be) and likely will at some point start behaving like one.

Even if this does not happen in a reasonable timeframe, it is indeed a question how long it will take before chromium itself is corrupted by the same influences.