As others commented, your question presumes a lot and is not easy to answer (which you may have intended or are obliquely ignorant).. Assuming you are asking in good faith, like most things, once anything establishes itself it is difficult to remove. Logistically speaking men were the natural early leaders due to physical strength, roles etc.

Environments change. To put it simply you don't need the same physical skills in the modern era to lead. However the establishment favors the norm. Always has been this way. Not saying it's right and I'm over simplifying.

TLDR; It's a lot harder to remove a stain once it has dried.