After you drop the package off at the shipper, most of the handling all the way to the recipient is done by machinery. Conveyor belts guiding the package to the next destination in their system. This is done with barcodes, these machines read barcodes, they do not read handle with care, fragile or anything else.
If you ship a package and it lands up first in a hamper, and the next package for that same destination is a 60 pound box of books, your package better be good enough to handle the box books falling on it.
Between my wife and I we ship about 30 packages a week, and receive about 20, in the last 5 years I can remember one of our packages being mutilated by the post office and 2 by UPS. On the other hand, we have gotten a lot that have been demolished by the shippers. Almost everyone of those packages were poorly packaged. Over all I figure the percentage of screwed up packages at less than 1 percent, that record is better than what I could do. I am far from perfect, as is the USPS and UPS, so I use them, pack it well and hope I am not in that less than 1 percent that self destructs because I failed to pack it good enough for the machines.