I have thought of a somewhat similar model myself, where a contract can store objects with a user account, with that user’s permission, which the user would then need to pay rent for. I do increasingly agree that it has advantages; the main one I see is that if a user account does get hibernated, reviving it and all of its associated assets requires only a single set of Merkle branches.
This seems like a promising direction.
I disagree. Like in the current ERC20 Token model, in the current world, shares of a company for example are maintained by the issuer, which means the company.
So technically the issuer pays for the bookkeeping It should be the same in blockchain and the issuer should be responsible to pay for the rent cost.
Does the base protocol need to be opinionated about this? If each contract is responsible for its own rent, each contract can set its own rules about who can pay for its rent costs, and multi-contract structures can be used for delegating rent costs.