Thats one thing I don't understand about hypergamy (dating app data proves it), why would a woman be in a situation in which she is easily the second, third wheel or worse
I think it's a direct representation of how unequal the power in society is.
Being the 10th wife of a price is better than being the first wife of a commoner somewhere like Saudi Arabia (as an example - can pick any society with high power inequality) in terms of the chances of reproductive success of your offspring.
Status signaling to other women, I imagine. But perhaps also media/social media fueling these unrealistic expectations and incorrectly normalizing them.