LOL I just got $300 worth of watch lubricants.
Packages, within packages, within packages. All this was within a box that was packed by a human so of course it was within a tiny flat rate box. But Amazon relies on conveyors and automation and those envelopes they use require an entirely different set of processes. For some reason Amazon stores their batteries in the "box" section of the warehouse as opposed to the "envelope" section of the warehouse so a box is what you get.
When I get watch batteries from Esslinger or CasKer they show up in padded mailers. When I get them from Amazon they're in boxes. It's the most cost-effective approach from a gestalt point of view because material handling is their profit margin. Meanwhile I ordered an adjustable height workbench from Home Depot that was damaged in shipping. I had to meticulously repack all the styrofoam and haul it back to Home Depot... but then they sent me another, all 150lbs of it, next day air AM from the opposite coast.
The costs of shipping have been completely buried by the externalities of logistics.