Ads already ruthlessly exploit these people, taking their money in exchange for garbage products. LLM might make this worse, but we have already automated displaying targeted manipulative messages via ad networks. People who can handle manipulative messages from ads should be mostly resistant to manipulative messaging from bots.
Not necessarily. LLMs at the model of GPT-4, and eventually above, affect the economics of advertising. Currently, there's only so much sense in optimizing your ads before it's cheaper to just spam more of it (er, "increase exposure"). LLMs will make it cheaper to optimize the ads further (i.e. get more bang for the same buck), so I expect the baseline manipulative effect of most ads to increase.
It's one of the end-game consequences of the change in advertising economics I mentioned: with costs of future AI models going down, eventually companies may be able to afford to generate individually personalized and highly persuasive ads on the fly. A personal dedicated con artist for everyone, indeed.
In fact, the odds are extremely high that you, me, and everyone else here has been taken in by some kind of ad or ad-like rhetoric and internalized it as just being normal world-view.
If there exist those who haven't even been fooled in such a way, they must certainly have the self-awareness to nevertheless entertain doubts on the matter.