PO boxes cost and I still need to provide my name, SSN, email, phone etc even if I'm not ordering online.
If PO boxes were free, it'd solve one part of which I take issue with, but it costs like 4 euros per pickup. If your income is low, the 4 euros on top of the some 20 euros for banking and another 20 for a cellular plan will quickly add up.
So you're thinking like a virtual mailing address as a service. You receive and forward people's mail. Seems interesting. Also kind of high risk for the service provider. People will use something like this to buy guns and drugs and other stuff on the black markets. But I guess they do that anyway. You would have to be prepared to deal with a lot of subpoenas to unmask the real mailing addresses. Could be a useful service though. Be sure to charge a lot for it.
My idea would have to be implemented on a national level. I take issue with the socio-economic injustities in the current identity and personal management solutions as they're not technically accessible nor free while still being simply a must have in order to do anything in Finland.
Isn't this essentially a URL shortener for post? The post operator generates an ID for your address, sender uses it to post stuff, the post office maps it back to the address. One additional challenge I see is that if the fees vary by distance, the sender would still get some sort of an idea as to how far away you are, but that is probably acceptable.