Digital ownership is enforced by laws and nothing else. There is no amount of code that can technically prevent me from copying any data that lands on my system.

>Tokens signed by an app-trusted key solve the problem with almost zero resource cost.

This ensures safety against access and not against copying. Of course I can not copy assets I don't have access to but the same is true for NFTs.

I’m not aware of any legal protections available to the person holding the private key that last signed an NFT. Digital property rights are enforced by client apps / DRM as well as legal trade agreements, but legal enforcement will be based on traditional registrations and won’t cover on-chain NFT transactions. You can buy my house’s NFT, but I will still legally own my house. Since, as you point out, DRM can always be broken, there is effectively no enforcement of NFT property rights at all.

Please refer back to my original comment about people hearing NFTs and for some reason which I fail to understand jump to "physical property". NFTs do not work for physical property but they do for digital.

Enforcement of digital rights is actually easier via NFTs than contracts/client apps etc. because NFTs mathematically can prove ownership (courts just have not caught up yet).

It can be enforced by hardware, and by not allowing the digital asset to be accessible on a system without hardware restrictions present.

As all things, technically, theoretically possible to circumvent, but you can make it exceedingly difficult.

No, you can't. Netflix, Youtube etc. (arguably the largest players in the digital properties game right now) have demonstrably failed to do so.