TL;DR: there are existing solutions, micro-formats for example.
You're right. No research was done. Author just threw information that he thought was important into a text file and called it a day. RFC 5785 says to put the file into the .well-known folder, the author only thought about United States addresses when making this, and as you stated the problem has already been addressed.
The only thing I know is that there is a problem local businesses and website providers have. And there isn't an efficient solution yet. I've propose a solution so we can discuss it and see if it makes sense. That's where we are now.
About going international, I'm from Spain, so of course I will be the first one interested in having an international "standard". People are already giving suggestions in github!
Looks like you made a worse version of hcard, http://microformats.org/wiki/hcard.
Adding a frontend to keep a hcard updated would be what makes this more accessible for business workers/managers.
I've used this on one site for several (six??) years or so, examples at http://microformats.org/wiki/hcard-examples-in-wild-reviewed.