This is interesting because the shift I'm describing is that my preferences as a buyer are as valid as the seller's. Me having preferences doesn't invalidate the seller's preferences and their preferences don't invalidate mine. I think negotiating could help people establish a sense of self-efficacy, or at least, a sense of where their self is effective and where it isn't (and give them information to change their self to be more effective if they want).

The other thing I think I've learned recently is that it's more unnatural for negotiating to be absent, because in low information markets like those we evolved in, negotiation is required to establish fair prices. So markets are either high information and don't require negotiation, or they're low information and without negotiation, they're unfair.