When you move to a new home or office, you can keep the same "Postal Domain Name", but change the address associated to it. Once.
Not sure how to convince all the big entities to use it, but it could catch on if you could convince some smaller companies to allow users to use it in their account settings.
I'd also wonder if financial institutions can use such a service at all, they probably have some stringent requirements to change the address of a person and are obligated to keep an address on record (at least in Israel they are).
I've never heard of anyone being able to send mail to a person using only their name on an envelope.
You would have a unique "ID" which you can assign to any physical address. This is all you ever give out. If you move, you update one record, and your mail will come to the right place.
It's similar to a website. If HN moves to another server, everyone doesn't have to update their bookmarks to point to a new IP address. Instead, they visit the same URL as always, and it automatically sends everyone to the new IP.
<his nickname>@<division>.<company>.<country>
so it should have been fairly easy to route.