The government enforces property rights though, so it's not a matter of distributed consensus, it's a matter of who the government views as the rightful owner. In a property dispute, a court might look at a number of factors: occupation and use, maintenance and upkeep of the property, paying bills associated with the property, registration of a deed with a title office, etc.

A digital signature on a blockchain somewhere means nothing. How do you connect it with the real property? All of the other above things go some way to demonstrating a real connection to the property. A block chain does not. It's the same problem all blockchain solutions have: verifying the data at the point of entry to the block chain. If that is distributed and can not be trusted and verified remotely, then the existence of it in a block chain does not help.

I'll create PropertyBlock™ blockchain tomorrow and sign a block with your property address it over to myself. Worthless.