You're right, car buyers generally don't expect a refund from the dealership when MSRP changes or there is a new incentive offered. It's a done deal. That should surprise no one. But what about the case where two different new car buyers at a legacy dealership buy the same car, with the same options, on the same day, and pay wildly different prices. It comes down to negotiating skill and potentially even dealership sexism, racism or what religion you happen to be.
It's one of the most distasteful things that happens at legacy dealerships, everyone gets a different price, so it baffles my mind how people think a simple price adjustment is somehow wrong and that previous buyers should be (compensated.