I'm curious about that too. It would make you think that the demons favored Crowley to accept him as their King... but makes you wonder what he exactly he did to make all of the demons end up turning their backs on him towards the end of the last season. Is it because he wasn't playing by the usual rules? Like working with the Winchester boys and Castiel - an angel? Or was it something else?
Maybe with Crowley being partially cured, we'll get to learn more about Crowley's backstory in the new season.