You are too focussed on dirt world goods. In the virtual world, growing inexorably into the matrix, the purchase of goods will be crypto currency for crypto good. A crypto good could be a piece of artwork with an embedded public key. You buy the private key. The digital art can be copied of course, but nobody else can verify the good except you, with your private key.
My last sentence is confusing. You sign a challenge with your private key. Anyone else can verify the signature with the public key in the good. That’s how they know you own it.,