I'm imagining a world where there are multiple adsenses (ad brokers) competing effectively with each other for space, driving out supernormal profit for brokers, and returning the bulk of the advertising revenues to the publishers rather than to the middleman (currently Google). With more revenue for the publishers, more publishers come online and drive out supernormal profits for publisher too. That would be a more efficient market.
With more revenue for the publishers, more publishers come online and drive out supernormal profits for publisher too.
We've been seeing that for a long time...In the mid 90s porn affiliate stuff would pay tens of dollars per click, from banners!
*By "publishers", you mean people that make websites with content that have ads.