This, I think is because we are becoming more aware. It’s more gratifying for a man to have feminine qualities because loving makes a better life. For women to be more masculine means she will go to bat for her children, making them feel more secure.
The reproductive systems of the two sexes are so vastly different. I don’t see how the two sexes become more alike.
Going to bat for you children isn’t a masculine trait. Mothers of all species are notoriously protective of their offspring, I think that is an extremely feminine trait.
I think it is more like people are becoming more accepting of different traits in different people. It is ok for women to like to do ‘male’ activities. It is ok for men to like ‘female’ activities. It is ok to be more emotional for men and not keep it all inside. It is fine for women to be more aggressive in their personalities.
We are just moving slowly toward everyone being equal and accepted, in some societies. It isn’t like that all over the world. Many countries still stick by traditional roles and are hell bent on keeping it that way.