Hate to say it but online purchasing is not environmentally sustainable. Millions of trucks delivering cat litter and O-rings is not sustainable.
Two hours and three gallons of gas if I run in to ace hardware for an o-ring.
One truck to a bunch of houses to deliver or countless cars started and driven to the store. Sometimes store to store in search of just the right item.
Cardboard is 100% recyclable.
The box is in a box so no one can see whats sitting on your doorstep before you bring it in. It might just be an o-ring but it might be a $6000 camera.
The packers at Amazon don't randomly decide which box to put it in. The computer tells them which box they have to use. Sometimes it's weird and they roll their eyes when they pack it just like you do when you unpack it.
Couple days ago, Jerry, my UPS man delivered a new television. It wasn't in a bigger box and was pretty obviously a television. He rang the doorbell and when I answered he said "It's pretty heavy. Where you want it?"
By the time I wobbled into the living room behind him he had it open and was pulling it out of the box. He put the legs on it plugged the PS4 in and was out the door in under 5 minutes.
It's not just sustainable it's preferable for most things. We'll always need greengrocers and butcher shops for fresh ingredients, meats, and dry goods, but even these local establishments have begun offering home deliveries again, just like you could back when America was great! Huge inefficient malls are closing in favor of a system that works out better for everyone.
