Finding a decent program these days is like panning for gold.
You can say that again.
If G or Y showed they could knock out part of gambling search results the DOJ might say, why can’t they do all of them?
But you might get a similar effect if affiliates ever organized and threw all of their traffic behind one room. That probably isn’t very likely to happen either though. But, personally, it would be fun to watch affiliates A) find a room that everyone pretty much trusted, 
grow it to be a huge room in the market, which would lead to C) even more income because everyone knows with huge amounts of poker players it just attracts more – lots of fishies.
Still, even if it happened, you wouldn’t know if they would dump their affiliates in the end. Proably why a lot of people diversify so much in their marketing.
From day one, I always though it looked better to just promote one (possibly) two rooms on your sites. If someone asked for your recommendation for a car, would you list 10 of them? No, you would narrow it down to 1 or 2 that you really believed was/were the one(s). But this is the position they left a lot of us in, picking between what we truly thought was the best and weighing that against will they still be around in present form (aff. income wise) in 2-3 years. There are affiliates that have just about all of them listed on their sites – probably because they are trying to narrow their future risk if a few go belly up, decide to screw them, etc..
The handwriting was on the wall when a bunch of them started allowing rake back to be introduced.