I am saddened that it has happened so many times, and I think your photo essay says a lot. Unfortunately, a lot of sellers and traders will try to continue saving a dollar or $1.50, thinking they have found the secret to packing a chip in a way that tricks the post office clerks into a lower price. Marking a letter as non-machineable does not guarantee it will avoid the crushing power of the sorting machine. With millions of letters going through the system, no one inspects each one for "non-machineable" markings. Only larger items (such as packages) avoid those crushing/bending sorters.

I have said before: just because a seller does not receive a complaint doesn't mean everything was fine. I have "swallowed" broken chips and postage due without complaining, and I am sure others have done the same (granted, I do not deal in high-value chips).