[stuhood]

To be clear though, any such consensus _could_ theoretically be modeled using a smart contract between multiple parties, including how ownership was to be revoked (e.g. "party `X` owns thing `z` unless party `Y` says otherwise").

The challenges are in:

1. knowing ahead of time what the parameters and participants of the contract need to be ("I own the house I paid for... unless 'the government' invokes eminent domain")

2. finding the usecases where it's even beneficial to store proof of ownership in a distributed fashion (rather than at, for example, town hall).

[munificent]

> To be clear though, any such consensus _could_ theoretically be modeled using a smart contract between multiple parties

Sure, but it's only a model, in the same sense of "model" as a model train set.

If you want that blockchain's consensus model to actually do real things involving real humans, then the humans have to agree to act on that model, which itself requires consensus. So now you have two consensus systems.