Advertiser's on Google and Meta et al are not really paying for visibility - they are paying to achieve some objective (e.g. sales) that is directly tied to a campaign. That's why digital advertising is so much more powerful than non-digital.

The question is, will LLM's as an interface be worth the spend in relation to converting without throwing users of chatGPT off over-time, all whilst, doing it within the regulatory frameworks. That's difficult to say. OAI will face a lot of scrutiny in EU for sure.