Honestly, not even bothering to solve the "double spend" problem makes this much less than it could have been.
After all, it is very easy to solve the "double spend" problem without the use of a blockchain: simply use a single trusted authority.
You know how every time you buy a house or piece of land you have to get a state-licensed notary to verify your identity, And then after signing the deed you have to send the paperwork to the county registrar because if they don't write it in their books then the land hasn't actually changed hands? That was NFTs working fairly well long before the invention of blockchain or computers or cryptography.
After all, it is very easy to solve the "double spend" problem without the use of a blockchain: simply use a single trusted authority.
You know how every time you buy a house or piece of land you have to get a state-licensed notary to verify your identity, And then after signing the deed you have to send the paperwork to the county registrar because if they don't write it in their books then the land hasn't actually changed hands? That was NFTs working fairly well long before the invention of blockchain or computers or cryptography.