I suspect that amazon specializes in arbitrage. They collect information in a domain (such as delivering stuff to places in a region). They build a detailed m

I suspect that amazon specializes in arbitrage. They collect information in a domain (such as delivering stuff to places in a region). They build a detailed map of "easy to deliver" and "horrible to deliver" locations in that region. After that, they take the "Easy to deliver" places for themselves and get a 3rd party to agree to deliver the rest, typically based on some rate scheme that is coarse to assume "average delivery pain" when in fact they're getting only the impossible delivery list.