Meaningful anecdote: I was talking with my girlfriend about what she and her best friend did in college. They both spent considerable time in college and attained masters degrees in respective fields that should have made them quite economically productive professionals. Yet, neither of them work in fields even remotely related to their masters degrees. In fact upon graduation, they both spent a number of years working menial, entry level customer service jobs. Years later their college degrees have benefited them zero. They both chose jobs that fit their are comfortable and unchallenging. They chose not to really aggressively compete in the marketplace. I really don’t look down on them for this — they just did what’s more natural for women which is work that is social and not particularly laborious.
And that explains why women’s work is valued less. Not all, but the majority of women will choose the most comfortable career or work, whereas not all but most men will chose to really bust their asses doing the most economically rewarding work.
You don’t need to invent this conspiracy theory of an evil patriarchy holding women down when evolutionary psychology perfectly explains the economic disparity between sexes.