Why can't United States Postal Mail be like IP addresses?

It's Friday, so I try not to post about Autodesk Labs.

Way back in third grade when I first learned how to address a letter, the form was: name, house number and street, city, and state as in:

Mr. Richard Feder
29 Elm Street
Fort Lee, New Jersey

On July 1, 1963, the United States post office starting using the zip code. ^{source: inventors.about.com}   The zip in zip code stands for Zoning Improvement Plan. Each address in the United States was assigned a 5 digit code. To this day, this expedites the delivery of mail. A postal worker or machine can use this number to route a letter or package:

Mr. Richard Feder
29 Elm Street
Fort Lee, New Jersey 07024

In 1982, the post office then added zip plus 4. ^{source: wikipedia.org}   The additional 4 digits define a more precise location such as a city block:

Mr. Richard Feder
29 Elm Street
Fort Lee, New Jersey 07024-7521

As a few Autodesk employees discussed on Yammer recently, once you use a zip code, the city and state are redundant. Why can't we just address letters without them? Furthermore, given the zip plus four concept, if house numbers are truly unique within a block, then it should be possible to extend the zip code to include the house number and send a letter as:

Mr. Richard Feder
07024-7521-29

This would make physical locations just like IP addresses - numbers assigned to each device that is part of a computer network that uses the Internet Protocol for communication. For example, see where this takes you:

http://132.188.65.54/

The wondering is alive in the lab.