You're defining 'successful' in monetary terms while I'm more concerned with the psychological health of the working environment.
I'm saying women are better managers because they are less prone to the types of socially tone-deaf interpersonal problems you see lampooned in Dilbert.
In other words, if I had to choose between a male manager who could create a succesful company versus a female manager who knew how to foster a harmonious working environment, I would choose the harmonious working environment over monetary "success" every time.
In the end, what does it matter to me if the company I work for is financially successful or not? On the other hand, if my manager is able to help create an environment that is more pleasant for every involved, that's something I'm interested in and that's where I think women in general are more naturally capable than men.