None of the good agencies do this.
I can completely believe both sides of this: the original Fishkin article, and this rebuttal which claims that "actually, marketers are competent and knowledgeable".
One way to look at this, mindful of [Sturgeon's Law](https://en.wikipedia.org/wiki/Sturgeon%27s_law) stating that ninety percent of everything is crap, is that good marketing agencies will rise above, but if I own a store selling scented candles and Google "online advertising" and hire one of the random agencies listed, maybe, just maybe, I'll get one of the 90% of bad ones that will try to hoodwink me into believing unsupported incremental conversion numbers.
I’m also starting to see more often the game brands play if switching vendors constantly so that each vendor operates at a loss to try and win the clients business. But the client always leaves by design.
In the end of the day, they need to keep the lights on and it's not their money anyway.