Amazon offered 2-day shipping, then changed their free shipping from 5-days to 8-days, deliberately changing a luxury to a necessity so they could up-sell it to more people.

I know I was perfectly happy when packages that I ordered on the weekend arrived in time for the next weekend most of the time, and never paid for expedited shipping. It was only when most of those packages started taking more than a week to arrive that I finally signed up for Prime.