Perhaps the challenge is not the size of the internet (it's indeed big and easy to generate new content), but rather the uniqueness and novelty of the information. Anecdotally, looking at the first page of Google results often shows various low-informativeness webpages, where only a few sentences provide information and the rest is boilerplate, disclaimers, generic advice or plain spam.

Breaking the security-by-required-effort assumption of various human interactions, especially among strangers.

It used to take effort to voice opinions on social media and other mass-communication platform, making the public trust that these are authentic messages representing real people. The scalability of this technology breaks that assumption. This has started before, and LLMs take it to a whole new level.