Most of the old relic machines I buy on eBay are sold by people who don't know how to pack for the most part, despite my instructions. Most of these machines don't represent an investment of over $150 including shipping, but that is still not chump change for me.
That said, no matter the carrier, some items come through remarkably well, others, not so much. It just seems to be random mis-handling of the particular package. Heavier tends to be worse however. All 3 major carriers UPS, FedEx and USPS have mangled more than a few old reel to reels or portable stereo phonographs, and generally there are no replacement parts or people who would work on them beside myself, so damage claims as a practical matter are pretty much useless.
I guess it just comes with the territory.