As a marketer/rainmaker, I can assure you that I get much further with clients when I can cut their advertising and marketing costs, or cost per acquisition, than when I find them more profitable traffic and revenues.
My clients never scream, bring me the rain... They demand, "Bring Me More Rain For Less Money."
I think the dynamic going on is that people hate losing money, and when you find them wasted money they can save, they view it as "their rightful money,not something you got for them." In fact, saving them money that they were wasting can really rattle their ego, and make them feel like they were taken advantage of, and who wants to be the bearer of bad news?!
Making money for companies though is just not powerful enough to be the end all solution to rake in the dough.
Being able to find cheaper traffic and revenues to generate proportionately less traffic or revenue is a much bigger win. (i.e. if you make them $1000 at a cpa of $100 a customer... you are better off generating for them $800 for a $75 cpa... even though the rain is less, the cpa is better, which makes them look really good, and is a defensible place to be...