Pink tax has been debunked many times. You're not comparing the same products. Male haircuts are much simpler, male clothing is much simpler, and women's biogy is different.
If you really think you could make female products cheaper, which women would still buy, why wouldn't you? It seems like an insane business opportunity. I'm sure YC would jump on that startup pitch.
I wonder if it might all even out, at the end of the day.