I think if he stayed out till the 1980's he may have been challenged by that maniac Casso. He must have been a good boss who treated his men fairly, so there was no motivation to challenge him. It seems the bosses who wee challenged either lost control of the family, or were out of control of their own behavior. Albert Anastasia seemed to have made enemies in his own family. Castellano was out of touch with certain crews, but to be fair he had guys like Gravano under him who were disloyal, and the situation with Gotti trying to protect Ruggerio. Corello may be one of the most underrated bosses.