I do think women and girls fight more now than they used to. And, as you point out, they fight differently now. I'm in my mid 60's, and I can't exactly pinpoint when things changed, but they most certainly have.
I'm not a sociologist, psychologist or psychiatrist, so I would only be speculating as to when and how things changed. I can't help but wonder if it corresponds to when women and girls started standing up for themselves, and making their voices heard. Might that be termed the feminist movement? I don't want to offend anyone, but I don't know how else to put it.
I distinctly remember a conversation I heard when I was a junior in high school in 1969. I was riding to school with a friend in his car (before I got my own). His then girlfriend was sitting next to him in the front seat. They were discussing another girl who had been talking about my friend's girlfriend. The current terminology would be "talking shit," I guess. Anyway, my friend advised her, the next time the other girl opened her mouth, his girlfriend should punch her. His girlfriend replied, "but nice girls don't fight." It seems that was the way it was back then. Of course there were physical fights between girls, but they were rare. I've also read articles in more recent years by school officials who indicate in some schools, girl fights are more common than fights between boys.
I also think the movie and tv industries reflect this change. Back in the old days, mostly in western movies, when women fought, it was a good old fashioned catfight, with hair pulling and rolling over each other on the floor. But now fights between women are mostly martial arts fights, with kicks and punches, but almost no hair pulling or elements of the traditional catfight.
Personally, while I watch girls fight with fists, I much prefer the catball type catfight. I don't get as much of a thrill watching two girls in a stand up, toe to toe fist fight as I do when they are pulling each other's hair on the ground, in a body to body catfight.