I think it's pretty much this, advertising is lubrication for an economy of consumption. Word of mouth and aggregators (like yelp) can help people find solutio

I think it's pretty much this, advertising is lubrication for an economy of consumption. Word of mouth and aggregators (like yelp) can help people find solutions when they know of a problem, but ads inform/manipulate (depending on how you see it) people to know they have a problem in the first place. Also if you've ever written ad copy it's all pretty structurally similar: hook, problem statement, solution, testimonials, etc.