No, business managers are not always rational so individual situations that are sub-optimally profitable will certainly exist.  But in a big company with multiple managers, those who behave irrationally making sub-optimal allocations of company resources are not going to fare well in competition with the others.  Small companies that take on higher wage burdens than others will not remain competitive.  We are talking big money here, right, 20 percent.  Just no way that 20 percent can be absorbed in a competitive environment.  This highly political question of wage equity does not pass the smell test in the overall business world.  If you could save 20 percent, wouldn't you by hiring primarily women.