What's more, even in a perfect market as you describe, advertising will only ever represent the subset of the solution space for any given problem that involves spending money. With how powerful a voice advertising has, we end up training people to deal with problems by buying rather than doing/learning/making.
In a perfect market, the top ad would be for the best treadmill. You'd never see an ad for just going outside for a run.
In a totally perfect market, the park charges runners a few cents to go for a run, and spends some of that revenue on advertising the park to runners, and then they would outcompete treadmill ads (for some users).
The reason you don't see this is because free parks are themselves a market distortion.
In a perfect market, the top ad would be for the best treadmill. You'd never see an ad for just going outside for a run.