It's a kind of problem that should be solved by social norms and regulations. They are way too lenient right now, and the continued acceptance of advertising as a respectable occupation perplexes me.
The problem is there's only so much work that can be done in that area, and way more marketing agencies than quality work. The excess labor bleeds into mercenary work where advertising companies shill for whoever pays them, regardless of merit or ethics.
Marketing helps products that would succeed anyway based on merit succeed faster and harder, and also helps unseat incumbents who have inertia but a bad product. It also allows products that should by every right sink like a lead balloon lurch haphazardly above the waterline, leaving behind a wake of cheated customers.
Oh, if only we could trust people in marketing to refuse help to the latter.
In marketing there are these all the time. A company I worked for had this "style test" which new customers completed, and we suggested them a "personalised, designer-curated" items list via mail. It was not even ML, we splat them into three profiles based on the test, and made three different mails, sent each of them to the members respective profile. Each mail started with a title like "Your personalised style guide, tailored for you by our designers"... It's not a big blatant lie like saying "USA is a democracy", but still, it's a lie.