Women have never been all that important as a troop gender in field warfare for two reasons:
1) Physical strength and stamina. Women have less of it, period. It's medically provable, so there's no point in arguing it. SOME women are stronger and have more stamina than SOME men, but to do that, you'd have to screen the population for these extraordinary individuals, and if you're going to do that, you might as well go for men, since extraordinary men will still be stronger than extraordinary women.
2) Childbirth. No same tribe puts its women first in warfare since they have more important things to do. Women traditionally grouse about being "childbearing machines," but the fact is, they can do it, men can't. For the same reason, no sane desert tribe puts its only water-finder in the frontlines of battle, nor did even the Athenians put their best philosophers in battle armor. I imagine that in the distant past, SOME tribe might have put their women to war, but those would have had to have been sterile or their only resource (they had no men) or they would have been quickly outbred by more sensible people.
For women in command, strength is less of an issue, and they also typically have better survival rates, so we DO see some women in those positions throughout history. Today, women continue to hold a secondary importance in units like Marines and infantry, whereas they have typically forged further afield in the Airforces, where again, physical strength is not much of an issue.