Shoot, that's what Amazon does. They got Prime to burn less money by calculating which shipper is the cheapest to get to the destination on time, and ~~proceed

Shoot, that's what Amazon does. They got Prime to burn less money by calculating which shipper is the cheapest to get to the destination on time, and ~~proceed to ship it via LaserShip anyway~~ later started using first-party delivery when that became cheaper than dealing with a carrier (although they still ship via UPS in rare cases here).