Whatever clever crypto system you think of: if it needs to work for the general population, it needs to go hand-in-hand with UX.

Say your example: a user generates a pub/priv keypair locally and shares the public one with the government. How does the government know you’re rightfully sending the ID? How does the user know what they are sending? Can the app/website/tool/person at post office they are using to generate+store+send the public key be trusted by the user? How can the government give trust to the user that this tool/person can be trusted?

And there we have attestation again. Or walled app stores, or certification as we have for physical services.