There will, following this absurd law, be women on boards, which is the goal; but they will have zero say and power. Their presence will be purely for the so-called "optics" of it: Feel good reactionism. This is tokenism at its finest, boys and girls. If California chooses to be so stupid as to embrace this ideological idiocy, then California will shortly discover themselves to be in possession of female board members that are there for the photo op, and nothing more. Then these ladies, and the feminist organizations, will cry foul.
Place in positions of power those that are qualified, not those that meet a societal requirement. Only then will you have real success. If women want to be on a board, that's fine, but you must first prove that you belong through your merits, not because you happen to be the proud bearer of a uterus.