I don't think priority mail is automatically insurred to $50 or $100. I know express mail is, but don't think priority mail is. As the OP stated, he is S.O.L.
Yes, I understand they do millions of packages and letters, and very few get lost/damaged, but you should accept responsibility for the ones that do.
The OP states the vendor shouldnt be responsible for covering it because it wasnt their fault
but they could of packaged it better with more bubble wrap, but I didnt see how it was packaged so who know if they used enough bubble wrap. But based on the pics, no amount of bubble wrap could of protected that
looked like a truck ran over the corner of the box.
I have friends that work for the post office. They say packages get abused big time
but thats what I heard. (of course I heard fexed/ups employees throw packages too) Im over paranoid. I always use twice as much padding/packaging as most people. Ive seen some fd up packages in my time.
USPS still handles the packages, and bundles them, and put them in large containers. Then they have the transit outsourced to airlines or fedex, etc
So if it was damaged it was most likely because of the handling by USPS personel, not other companies.