line sharing metro dark fiber and line sharing residential are TWO totally different things. So stop trying to say that it does exsit. That is not the topic at hand.
And you'll NEVER find that carrier-neutral company to build that FTTH/B network on a national basis. Shareholders of that company will want their money back at some point and by doing the wholesale- you're not gonna be able to fully say "yah we'll be able to repay you at some point" as like Comcast and others are able to say.