I disagree with your the premise, "had Vito never been imprisoned". Same thing could be said with Paolo Violi who was also imprisoned when the Rizzuto clan made their moves. Frank Cotroni was also imprisoned.
Not really because Nicolo was already making moves before Violi was locked up. That was why he wanted to kill Nicolo but never go the ok to do so.
In Vito's case you didn't hear shit until he was locked up in Supermax.