How come there are more great actors than actresses?

Jack Nicholson, Leonardo Dicaprio, Al Pacino the list goes on and I don't see as many good female actresses on the screen as male actors which seems strange to me since women are always considered to be the more expressive and emotional than men. Also on a general level I think most male actors perform better on screen than women. Most women I think come across as cliche and shallow. Could it be that men are usually better actors than women? If so: how come?