It's interesting that 3 studies came up with the conclusion that the business model of the USPS is so poor privatization is untenable without considering the fact that maybe privatization would come up with a better business model. Right now, the USPS is a government sponsored monopoly that is failing spectacularly. Allowing private companies into the market might not only improve the business model but come up with something fantastically different that fits the needs of the consumers.

Looking at a failed business model and saying "That model is so bad even private companies couldn't fix it" seems like putting the cart before the horse. Private companies are going to find their own business model, one that isn't terrible, because their livelihood depends on it.