I think you've hit it on the head here. I used to do ebay sales for a living in a physical storefront several years back. Even as far back as the mid-2000's you couldn't win a "not as described" claim.
Typically what we would have happen is a buyer would send an initial contact asking why something wasn't included, or why some scratch or dent was present. We'd point out where it was listed in the pictures and most likely in the description. Then the buyer would immediately escalate it to a "not as described" claim. It never mattered one bit to ebay or paypal what evidence we provided, we always lost.
Even so, at the volume we were doing it was just a cost of doing business. What really cheesed me off were the actual "Bad Buyers" who would do the claim not as described, and provide a fake tracking number for the return shipment. You couldn't get ebay to believe that a tracking number that was for a shipment to a completely different city wasn't evidence that we had our item back.