Really late comment but I agree with this. The Smurfette Principle is lame.
I don't see the big deal at all.
From Goranger to Dynaman, it was one girl or at Sun Vulcan , none. That's 0-6.
From Bioman to Maskman [4], it was two women and from Liveman to Turboranger [2], it was the typical one girl. So 4 for the duo and two more for the typical bringing this to 4-8.
Then from Fiveman and Jetman [2] there are two girl teams, and Zyu-Kaku [3] had the initial one girl setup. So 6-11.
From Ohranger to Megaranger [3] , we again have two girl teams and from Gingaman on to Abaranger [6], its one girl teams. 9-17.
But from Dekaranger to Boukenger[3], we again have two girl teams and then for a blip that's Geki, its one girl. So now 12-19.
Goonger-Gokaiger [4] has two girl teams, so not bring this up to 15-18 while Gobusters and Kyoryuger is one girl. So, 16-21.
16 two girl series in the midst of 21 one girl series, that's very impressive to say the least when it started with a male dominated series that had a few women here and there and by many respects , did them justice from what I hear of them for their era.
Smurfette Principle is now the female equivalent to Godwin's Law.