At the end of the day, the vehicle registration agency still needs to issue the license, so what's the benefit of a blockchain here? You do not need a blockchain to, say, cryptographically sign something such that it can be verified as a genuine item. And blockchain won't stop corrupt minting of licenses by the agency. And even if you did need a blockchain, the ledger wouldn't be public because the data on it is private. So now it's just a database with a ton of extra steps, complexity and kneecapped performance.