The point is that in this situation, soner or later, all poker affiliates will have to take a 20% paycut in order to stay in business, since in the long run it will be impossible to compete against rake back sites without taking a beating oneself.
Right now rake back affiliates are happy, because wherever they are able to reach players they are able to convert them in record numbers. It is profitable to do rake back at this point.
Now, once the non-rake back folks are forced to take the pay cut to survive, everyone suddenly loses.
The rakeback folks will have lost their edge, and everyone will make less money than the programs promise.
Who wins? The program, for a short while. They get to have the affiliates pay player incentives out of their own pockets, something that is normally done by the poker room.
Next thing affiliates will continue to underbid each other until promoting poker has become completely unprofitable.
On the way there, the quality of promotion will decrease and decrease because it will not be worthwile to spend a lot of time or money on promoting poker.
Having affiliates do rake back is extremely short sighted and will end badly for the poker industry if it continues.