Perhaps it's just a problem that college students have when they move to a new dorm every year - but I don't think so.
You see, physical addresses are incredibly problematic - not the least of which is that they're impossible to change. If I subscribe to several magazines, then move, I have to call up each magazine individually to change my address in their files. Plus Amazon.com, my bank, phone company, etc etc etc. Moving is a huge hassle, and having to change addresses in so many places certainly doesn't help. Or, if you have a summer and a winter home, how do you tell every service that you're connected to to send packages to one location in the summer and the other in the winter?
Another problem with addresses involve privacy. If you give someone your mailing address, odds are that you are also telling them where you live. Who knows what will happen to that information when the company's servers get hacked?
Now, in the online world, changing "addresses" is easy. You just point your old email address to your new one, or email everyone in your address book. One click, and done. You can even give different addresses to different people (many people create separate email accounts for spam) and set up complex forwarding rules. None of this is possible with a mailing address.
I challenge you, the budding entrepreneur, to solve this. Create a service where you create psuedo addresses for people that they can give out to businesses and other people. At any point, they can change the end point of this psuedo address, and all of their new mail will immediately be sent to their new address.
The most obvious challenge is around shipping costs. If their mail is sent to you, then you send it out again, someone has to pay for that extra postage. Maybe you market it to the rich and privacy-concerned who don't mind footing the bill. Or, maybe you make it entirely virtual, and work with online retailers and/or the post office to integrate your digital address book system with theirs, so that the packages go straight to their correct destination.
I used to believe that physical mail was on its way out - but I was wrong. Emails have replaced letters, its true. But online shopping - and package shipping - is at an all time high. It is becoming easier and easier to get a product sent to you than to go out to the store and buy it, and that trend is only going to continue. One day, 3D replicators will eliminate this need - but the ability to 3D print sneakers and electronics at home is easily 30-50 years away. That's a lot of time for you to be rolling in money, and a lot of time for humans to deal with the broken physical address system.