Exactly this. And it's not really possible to do repeatable trials, it's all just vibes. People have very little awareness of their own cognitive biases.

And companies have high awareness of this all.

They have a way to decrease cost and probably increase token consumption, with gradual changes and no abrupt jump in capabilities, and users have no way to reliably detect it.

Market will advantage companies that do it.

And they are in the best position to automate online narrative shift (the real LLM killer application IMO) towards "Users are imagining it".