More wild speculation, but it seems like this may be a part of our problem
Bloggers mostly read other bloggers and write to impress other bloggers.
Economists mostly read other economists and write to impress other economists.
Scientists mostly read other scientists and write to impress other scientists.
Journalists mostly read other journalists and write to impress other journalists.
Republicans mostly read or listen to other Republicans and write or speak to impress other Republicans.
Democrats mostly read or listen to other Democrats and write or speak to impress other Democrats.
And so on.
By dividing up into our little hermetically sealed subcultures and sub-subcultures do we stop making sense to other groups? Inside vs. outside the beltway barely begins to capture it.