"E.g. apparently Bing is just as good as Google these days."
Well, when one of your "1000 ranking signals" amounts to "clicks on Google's search results", I would hope so. Of course, this just means they'll always be equal to Google - epsilon, even if Google's quality gets worse, and so like you say there will never be a compelling reason to switch.
Well, when one of your "1000 ranking signals" amounts to "clicks on Google's search results", I would hope so. Of course, this just means they'll always be equal to Google - epsilon, even if Google's quality gets worse, and so like you say there will never be a compelling reason to switch.