Quick game collector's rant of the day: If you're selling a pricey or expensive game online, do the buyer the courtesy of sending it via a first-rate and at least insured, method of shipping. Not Media Mail. I can sort get doing that if it's something the seller sold cheap, and they're not making much of anything off of the sale. But if they make a decent chunk of change off of it, they can afford to ship it proper and for the buyer's sake, should.
If a buyer expects that, they should communicate that. A seller is trying to make the most profit they can. And if it's on eBay, its listed what they ship it with.
No, no one should be shipping games media mail. USPS explicitly states that video games are not eligible for media mail.
Also, regarding ebay, I see very frequently sellers listing items with non-descript shipping method or they list one thing and then ship another. That's still on the seller. Also, ebay does let sellers list media mail for items sold in the video games category and they really shouldn't be allowing that, but that's on ebay.
Also, it's on the seller to provide proof of delivery and insure the package and all that stuff. Until the product arrives in the buyers hands, it is on the seller to protect the product. Normally sellers charge for such things, but that's on the seller to charge for it or accept the risk. That's why that stuff doesn't fly where sellers say "buy at your own risk, shipped untracked/uninsured" because you can say what you want, but it doesn't mean anything against paypal/ebay/chargebacks/etc. CYA or accept the risk.