Honestly I think Rizzuto would have come back strong no matter if they turned on each other or not just because of his power. Yes they did make a power grab when he was away (they wouldn't dare do it with him there and alive) but to see people still getting clipped proves how much influence he had/has in the GTA. While I do think it would have taken him longer to gain control that it did when he came back, I still think it would have ended up with Desjardins/Montagna/Di Maulo all dead.