[marc28443]

I think you are conflating a call for action with an idea for a startup. To be more effective you should focus on one of these only.

As for your proposed solution, such services already exists, i.e. webfinger which Google may be supporting in the future.

So the challenge is really, how to enable widespread adoption for webfinger or something similar. If you have an ingenious idea how to support that, lets hear it. Because you are right, it would mean a lot of progress for the web.