It's an interesting idea, kudos.

Sadly, this will always be a game of cat and mouse. I wonder if it was ever avoidable for the internet to become a hundred of such games at once, between advertisers and ad blockers, trackers and browsers, hackers and developers, search engines and SEO experts...

If your concept took off, someone will make a program that inputs the LLMs text like a human would. It might still take some time (if it isn't possible to hack the timing records client-side), you'd probably have to get busy detecting multiple connections from the same IP, and then they'd work around it...