Yeah, but so was Vincent because he accomplished what he wanted... he got his foot in the door.
Interesting, at the end of the day he ends up a tragic figure as well.

His whole life was predicated on the glory of the Corleone family and his desire to be a major player in it. Just when he achieves his dream, he loses the love of his life (through Michael's cunning and an assassin's bullet) and he loses whatever power he had. After Mary's death Michael was finished, and Vincent reigned over nothing. You think Neri stuck around to help him? Not in a million years.