And I'd argue that's a far superior model. I go to eBay for a lot of items that I suspect may be graymarket but I'm willing to risk it, specifically BECAUSE I know exactly which seller sold me the thing, and I can go back on them if it's bad, and eBay has pretty good protections for buyers.

I could buy the same goods on Amazon but have none of the traceability or protections.

Plus Ebay incentives sellers to upload their own photos and written descriptions of the product they're selling, rather then having generic product pages for multiple listings.

If I'm buying a second hand item like an old video game or something I always use Ebay since I can see what the product actually looks like and can make my own judgement on condition based on the photos. Something you can't really do on Amazon.