The reason that less women are working as directors, is because of society. Men are recognized more than women in film productions, as directors, and actors. Women are also paid less in the industry. There are also problems with innapropriate behavior in the work place. Acting and directing are also a tough field to work in, I.e; pay, not being recognized, and not getting enough views.
One way to fix this in the future, is to pay women more, give them more recognization, and fix the issues with workplace sexual harrasment. The last one would be the hardest.