One basic hypothesis is that women are choosey. Dring human reproduction, women have to pay the enormous costs of constructing an entire human infant, delivering it (and their bodies are just barely able to fit it through the various obstructions), and then raising it for at least 10-15 years. (even ‘wild’ humans probably need to be around 10-15 before they are physically and mentally able to support themselves)
A man, in theory, need only supply a few drops of semen that he produces anyway.
This fundamental relationship defines, well, almost everything.
So if women have a much smaller incentive to have sex with men than men have to have sex with women, why do many women often take actions to make themselves appear sexier.
The short skirts, the makeup, the push up bras, the exercise, the makeup, the high heels…it goes on and on.
Since they have to pay a much higher cost if they get pregnant, one would logically and rationally expect the opposite. Women would wear whatever is practical, and they would not bother with many complex behaviors in relationships to make themselves more desirable, knowing the male has no choice but to take any offers of sex when they are made by the woman.
One theory is that women make a relationship with them expensive (they expect gifts of resources, exclusive attention, and so on), so they have to make themselves to appear more desirable to entice men to pay the large costs that they themselves charge.
I guess this sort of answers the question. But it seems contradictory and almost like doing one thing, then doing the opposite.