That's true now because it hasn't proliferated yet, but I don't think it will be true for much longer. I think there will be tipping point. When AI-generated content competes with AI generated-content to game the ranking algorithms driven by AI-generated user accounts that write AI-generated comments you end up with something that's not optimized for human end-users anymore.
> modern AI is not meaningfully better at generating low-effort posts than content farms are
It's not better, but potentially 100x cheaper. Not yet, but soon. That means a single developer in a 3rd world country can do the work of a content farm. Maybe you're right and that won't change anything, but I think it will.