If people (and publishers) started using the unweighted Metacritic score as the basis for their purchasing decisions or crazy bonus schemes, then there's nothing to stop them using another site with identical unweighted scores.
You seemed to miss my point. With that, I was not saying they need to outright scratch that system. They should simply offer a SECOND one that is unbiased for their users to choose. What publishers to with that is out of our hands, but it would be infinitely better for the customer.
Although, in a perfect world, this wouldnt need to be "weighed" in the first place.