I've come to this conclusion a long time ago. If consumers have perfect information about a class of product from different producers then advertising would be completely useless and the market for that product would be completely efficient (on the consumer side). Of course consumers don't have perfect information, and that's what the marketing industry claims their purpose is to address.

But really the role that the marketing industry (at least for typical products and services) actually plays is to selectively give information to consumers to influence their buying decisions against how they would behave in an efficient market. And then it's a very short and slippery slope to just straight up lying about products and manipulating consumers through their insecurities, which we see happening all the time with how the marketing industry has developed for the last few decades especially with online advertisements.