This is all relatively new in human timescales. My parents as children saw the start of modern advertising, with ads targeted at them. But they did not see entertainment engineered to sell them product. I think in the 60s you started seeing bands manufactured and aggressively marketed to youths (such as The Monkeys), because companies wanted their share of Beatles money. And 70s, when George Lucas and Kiss realized how much money was in branded merchandise. And late 70s, when He-Man reversed things and media was created specifically to sell merchandise. On human timescales, the results are starting to come in on this experiment.