I look at it this way, and see two counterpoints (though I could be wrong): 1) the product has to get to you anyway. Whether they do that in two days or a week

I look at it this way, and see two counterpoints (though I could be wrong): 1) the product has to get to you anyway. Whether they do that in two days or a week, it doesn't seem like the T+NUM_DAYS variable would impact the environment differently. 2) if not for rapid shipping, a lot more people would go out shopping at stores a lot more. A single truck making a lot of deliveries-- even though it's running for 8-13+ hours, may still be more efficient than all of those people making multiple trips to different stores to get what they need.