"Prompt trainers" and such will just be replaced by slightly better LLMs that can do that part already or inquire for further details from a user.

No, because Coca Cola doesn't have what plants crave.

Technically sodium is an electrolyte, so Coca Cola does have what plants crave.

I’m more worried about automated astroturfing and propaganda.

Well, it's a little late for that one.

Fire one of the many offline LLMs up on a university network or somewhere else that a single IP connecting many times won't be too suspicious and let it go to town.

Why? The only difference is that everyone can afford it. It is probably better in the end than only having paid chills doing it, since people will realize they can't trust "internet consensus" as being a actual consensus.

The real problem for some sites, is the amount of believable spam on mindless rant feeds, like Twitter and Reddit etc.