> Finally and most fundamentally, a land registry is by nature a centralized registry of holdings with a legal monopoly. Why on earth would you need to use a blockchain here, when an append-only database does the same job?
Records within an append-only database running on a central server can be altered or deleted by whomever has the root password to that server.
The only way to guard against that risk is to replicate and publicize the data, make sure all data modifications are cryptographically signed and valid according the logic of the application, and incorporate into each new version of the data a hash of prior versions of the data, in order to guard against data deletions. In other words, to implement a blockchain.
> The hard part, you see, is defending their property rights. Local bigwig casually stomps on their land, now they need to convince the corruptible police to investigate (good luck with that when they're on the bigwig's payroll), find a lawyer willing to take this on (in exchange for what?), get the corruptible land rights registry to verify their claim, get a corruptible judge to give a true verdict, and then convince that corruptible police to carry out the verdict. If you're a poor subsistence farmer, it's nearly impossible to navigate this morass, and blockchain solves precisely zero of these problems.
You have described a horribly corrupt and oppressive society. It's not what most of the developing world looks like. You are right that there is unlikely to be a technical solution to this level of oppression, except that it would be harder to implement in the first place in a society where property records were managed via a blockchain.