I think the real issue in this context is the 3.5% surcharge that Amazon may add, and whether or not elimination of USPS junk mail could ever make a dent in tha

I think the real issue in this context is the 3.5% surcharge that Amazon may add, and whether or not elimination of USPS junk mail could ever make a dent in that 3.5% figure. (My gut says that it would not; that the fuel use of junk mail constitutes a very small drop in a very large bucket. But I'd love to be wrong about this.)