"What would that look like?” Like... in some sort of idealized world? Or right now? Because those are probably two very different possibility spaces.

In fact, the thought of our current president getting control over a platform that has all posts linked to citizenship identity information (if I understand their proposal) shows why this would have been a terrible idea at any time, even if we might not have seen it then.

There was a line of thinking I heard once, that the USPS toyed with the idea of creating a national email system, which would be pretty much your official email address with the USG. The post office would be able to have you opt in to having certain physical mail scanned in and it would be treated as official correspondence. Sadly between junk mail firms and postal unions both fearful of lost revenue and jobs, it never got off the ground.