In my opinion women are much less sure of themselves and I think this impacts their ability to even attempt to build skills.

Women are also the limiting sex and so they are sought after and often times taken care of, which again, hinders the necessity for skill building.

Women in my opinion are much more prone to societal influence (per capita basis) and so they are disproportionately impacted by propaganda (advertisements / pop culture) and become hyper-fixated on their appearance and material goods. That fixation inward takes a lot of energy from skill building and aspirations beyond self-appearances.

There are obliviously exceptions to all of these speculative observations. But I think all do hold true more often than not in my experience.