>most writing on websites sucks, most documentation sucks, most FAQs are lacking severely and use vague language in answers that add confusion rather than remove it. I'm not sure if LLMs will really lower the average quality there.

That's mostly the case because software developers create a lot of these FAQs and documentations, and most aren't good at writing.

Companies with dedicated documentation teams usually have well-written documentation. It's just not the norm.