I said "or any other reasons" because I was in a hurry. Internet existed way before ads, I agree, but even then you wanted people to visit your site to see what you wrote. Maybe to become an expert in a topic, maybe to feel better, but you want people to know who did it. That's why websites used to have a webmaster and info about that particular person.
If people stop visiting websites because LLM give them what they want, websites will stop existing. Don't believe me? Check how many "fansites" exist now about topics compared to ten years ago, when there weren't social networks. They have been replaced by influecners with huge followers on Instagram, TikTok, Twitter and more. The same will happen.
What you describe in your last paragraph is still an evolution, not an extinction or disappearance. Fan/stan culture is absolutely huge on social media, where it has thrived, with single-person-ran stan accounts becoming as big or bigger than the heyday of blogging or fansites. So I just think we disagree on some foundational level.
If people stop visiting websites because LLM give them what they want, websites will stop existing. Don't believe me? Check how many "fansites" exist now about topics compared to ten years ago, when there weren't social networks. They have been replaced by influecners with huge followers on Instagram, TikTok, Twitter and more. The same will happen.