Largely abandoned? Hardly. Dresses and skirts have always been popular with women and continue to be so. Many women find skirts much more comfortable and practical. Look at tennis for example, where the tennis skirt has been worn by the most visible female tennis players for the last 25 years.
I agree that men and women are different, duh. The author's hypothesis is interesting. Personally I think the immodest clothes have more to do with the fitness craze in Hollywood. Anyway, I consider that I am very feminine. I am neither a mother or a wife, but I show my distinctness as a girl by my dress. Even when wearing pants I strive to look like a girl. I'm also kind and caring and offer nurturing to my nieces and nephews whom I adore. I like to decorate, and I love to sketch and write poetry, activities that have been traditionally viewed as feminine. I'm also a feminist and very proud to be one. But feminists are not a monolith of women who think exactly alike. I can only speak for myself, but what may upset some feminists is that the traditional role of women has often been looked down upon as inferior. That some guys take women being different to mean that femininity is not complimentary to masculinity but inferior. Also feminine differences have been used as an excuse to exclude women from things they can do which fall outside of their gender role. Incidently the same applies to men. Is a woman not a real girl if she isn't a domestic goddess? Is a man not a real man if he could care less about sports?