No different than a 20 dollar bill. If something happens to it you're screwed, and you better not have a backup of it. Just take good care of such items, keep them in safe places, and insure them however possible. I've got a couple hundred DVD's and only ever had one bad one. I took it back to where I bought it, without a receipt, but since they could still scan the barcode they let me exchange it for another. I realize that requires a willing vendor, with identical product in stock, but the point is I've got hundreds and never had a single unresolvable problem.
I don't agree with your analogy. "Mrs. Miniver' ain't a twenty dollar bill. We own our currency while it's in our possession, but we only lease the right to use 'Mrs. Miniver'.
The media makers want to say we don't own the product, we only license the use of it from them. But if the product becomes unusable, they then want to treat it as though we own the physical product and are personably responsible for replacing damaged product.
If we have truly paid for a license to use the media, then we should qualify to have the physical product replaced easily and inexpensively.
But the media makers want to play it both ways.
If you found a retailer who agreed to replace damaged product for no cost, that's great. But it's also highly unusual.