Part of the rationalization I have made for creating ads is that proper targeting gives exposure of products that people would actually need/want. When scaled up to millions of people this specialized ad delivery allows for much greater diversity of products and solutions in the marketplace. Ideally this should lead to less of a "winner take all" effect in a group of competitors and would allow for more niche solutions to be catered to and sustained.
Certainly I would never say this goal is comparable to anything in medicine, but the domain does have ambitions beyond simply making money.