> Then every agency would have to trust some central authority.
They already have to do that! The central authority has to issue the licenses in the first place. Unless you are suggesting some absurd, decentralized driver's license issuing? Even that is begging the question though, as there has to be some centralized process to decide who is allowed to issue driver's licenses.
> A.k.a. a blockchain. You don't even need to restrict write access; DMVs can readily ignore transactions by non-DMV entities.
Alright, you are really stretching the definition of blockchain. Like, lets say someone just mirrors the database. So there is a web interface, and someone else copied the whole thing down.
Does that now count as a "blockchain" lol? Having more that 1 copies, of a mysql database, is a blockchain now?
> The central authority has to issue the licenses in the first place.
The US federal government is not at all involved in issuing state drivers' licenses, last I checked. Nor is some international agency at all involved in issuing drivers' licenses within any given country. That's what I'm getting at with "central authority" - specifically, a central authority external to the issuer and/or validator.
> Like, lets say someone just mirrors the database. So there is a web interface, and someone else copied the whole thing down.
Is that person going to continually copy it down? What about data from other agencies? How many people are going to be using your web interface?
What I'm getting at there is that this all seems like an awful lot of work compared to just, you know, including some data in a transaction on any ol' existing blockchain (even Bitcoin or Dogecoin or what have you is good enough for this, let alone something that actually supports NFTs like Ethereum or Cardano) and using any ol' blockchain client/explorer to lookup whatever transaction got printed on the ID card.
> Is that person going to continually copy it down? What about data from other agencies? How many people are going to be using your web interface?
> What I'm getting at there is that this all seems like an awful lot of work compared
They are literally the same thing.
The definition of what a "Blockchain" is has stretched so much, that having 1 mirror of a database would now fit people's definition of what a Blockchain is.
Once we get rid of proof of work, and transactions, the only thing we are left with is "a database which has mirrors".
> Once we get rid of proof of work, and transactions
Neither of which I suggested getting rid of above (though to be clear, proof of stake and proof of burn both exist). Transactions are especially handy when you move beyond merely recording the drivers' licenses themselves and actually start recording things like, say, traffic tickets or new endorsements or what have you - and that handiness is significantly improved further when agencies are sharing a single public blockchain instead of trying to maintain umpteen different internal databases explicitly tracking each other.
Even taking your assumption that a blockchain and a database mirror are "literally the same thing", you're still missing the key difference: that the former gives you the benefits of the latter (or at least the ones relevant to this context) with significantly less effort. It's similar in comparison to, say, using IPFS v. mirroring an FTP server; yes, you can create a bunch of FTP mirrors, and reinvent a poorly-specified ad-hoc substitute for half of IPFS, but it'd be a heck of a lot easier and more robust to... just use IPFS.
They already have to do that! The central authority has to issue the licenses in the first place. Unless you are suggesting some absurd, decentralized driver's license issuing? Even that is begging the question though, as there has to be some centralized process to decide who is allowed to issue driver's licenses.
> A.k.a. a blockchain. You don't even need to restrict write access; DMVs can readily ignore transactions by non-DMV entities.
Alright, you are really stretching the definition of blockchain. Like, lets say someone just mirrors the database. So there is a web interface, and someone else copied the whole thing down.
Does that now count as a "blockchain" lol? Having more that 1 copies, of a mysql database, is a blockchain now?