the negative feedback is that any attempt to create quality, non-seo content is punished by being ranked low and so we revert to average/low quality of over-SEOed but low signal content.

Like other users have noticed, publishing a good recipe is not enough, you have to fill it up with useless fluff. and you have to make pretty URLs . And add meta the tags

This happens for tech advice too, like linux solutions etc

SEO content is a positive feedback loop.

That would imply there isn't an equilibrium.

And in this case, the equilibrium is some amount of AI-bait fluff. There's a limit, beyond which continuing to add more fluff does not produce higher results.

It's a dynamic equilibrium. The constant is bullshit, but the means of delivery vary.

I think OP meant "the system always gets back to the status quo where suggestions are near-useless", hence a negative feedback loop.

So a negative positive feedback loop?

Just positive feedback loop. The term "positive" or "negative" refers to the effects of the feedback path on the overall system, a negative feedback loop attempts to negate any changes in the outputs, while a positive feedback amplifies any changes.

Perhaps "Vicious Cycle" and "Virtuous Cycle" is better terminology in this case. Both of them describe self-reinforcing (i.e. positive) feedback loops, while also making clear judgement on the desirability of the consequences.

Just feedback loop*

Adding positive/negative on it is unnecessary specificity