My father once received a letter from Algeria, with 3 words on the envelope : his first name, "Créteil" (the town where he lived, ≈100k inhabitants), and "France". Of course, in the 70s there was no Internet nor central database to find him, yet the postal service managed to deliver the letter. He was a very active social worker, managed a youth football team, etc. which made him locally well-known by his first name.
Nowadays, many people can't find anyone or any place unless their phone helps them. And postmen never stop to chat. Such a letter would not pass through the technology process, and probably not through the human network.
I can say that at least where I live (Brisbane Australia's inner-ring suburbs) that's still the case: my postie is super friendly, loves my dog, and always has a couple of minutes to say hi!
And its great, because I live at a house number that is <number>A, and there is a <number>... but no <number>B or anything, which trips up a surprising amount of people/delivery drivers, so having a postie who cares helps
sadly, over here in the netherlands and I assume elsewhere, the job as a postman changed drastically when they privatized. room for the human element has been all but squeezed out for profits long ago.
Nowadays, many people can't find anyone or any place unless their phone helps them. And postmen never stop to chat. Such a letter would not pass through the technology process, and probably not through the human network.