"I think if we could manage to analyze that expenditure of money we would find that a vast percentage of it, probably one-half, is entirely wasted." - Robert Ogden, 1898.
I don't disagree with your comment, but wouldn't you agree that the last thirty years have introduced an unprecedented technology environment for tracking ROI on advertising? It seems clear that a lack of incentives, not abilities, is what keeps this racket afloat. For that reason, I'm not so certain that it will be allowed to continue forever. Once advertisers get a taste of real ROI metrics, they'll drop the hand-waving platforms overnight. Biggest market opportunity of our age?