Go to the toy aisle and see how many toys there are of the female characters vs. the male.
I'd be fine with a female red ranger (As long as there's not some contrived reason why she's red), but toy sales matter.

But how many girls within Power Rangers intended age group do you know that watch it? Men and women watching it is all well and good, but they're all but a fraction of the overall audience for the show.

These are also both very good points. Yellow and Pink shelfwarm like there's no tomorrow over here.

And how quick did Shinken Kaoru Red sell out?

The figuarts? It was an exclusive so I have no idea how well it sold.

The answer is quickly. Even on BBTS it sold out quick.

So the exclusive toy aimed exclusively for adult collectors sold out.
That's not a good example.

I'll get started immediately!

I would love a female Red, but Toei seems unlikely to do it anytime soon, and if Toei doesn't do it, Saban won't do it. From the Power Rangers side of things, it simply won't happen because while gender changing might be feasible for Yellow Rangers, who are side characters, to gender change a Red, who is the main character, would be too obvious and jarring.

Toei *might* do it, although it won't make much financial sense for them. Girl's toys simply don't sell well outside of collectors. Even when I was a kid, the Yellow and Pink Rangers shelf-warmed like mad.

That's a Figuarts, it's catered to adult collectors who LOVE female Toku characters.

Not enough for any of them to ever get a mass release though :lol

Such a shame isn't it? It's especially depressing for someone like Kaoru Shinken Red, who is both a RED and a legend represented (no less the Shinkenger representative) in Gokaiger, to not get a mass release.