Moving states requires validating the information from the previous state too. It's not a matter of the new state just updating an entry in its database. It's a

Moving states requires validating the information from the previous state too. It's not a matter of the new state just updating an entry in its database. It's an entirely new entry. Given that, in person validation makes sense. Moving within a state is simpler, and indeed can be done online in most states. Granted in many countries there's a national ID system. Also a part of the point of government-issued IDs is that there's more validation around its issuance, and many other parts of society take advantage of that.