I think you have hit on it but need to account for when these instincts were created and why a little deeper than you have although you have touched on it.
Perhaps it is because back in the Cro-Magnon era provisioning was far more about simply surviving than it was about luxuries and along with "primitive instinctual highs" and "social dominance gains" that came as one thing with the alpha male. However and certainly in modern western nations what you refer to as a "lower quality of life as a impoverished single mom" is in fact a life of luxury undreamed of by even the most privileged Cro-Magnon woman and in fact most women through all of human existence up until only a few decades ago. So with the basics of simply staying alive that concerned and heavily influenced our Cro-Magnon womans instincts (food etc) now guaranteed in our modern societies (and no longer of the slightest concern) all that is left are the "primitive instinctual highs" and "social dominance gains" to influence modern womens choices.
Sure you can say that in today's modern world her "relative" quality of life is lower than it perhaps could be but remember we are talking about primitive and primal instinctual traits from when the concern was simply having a greater chance of surviving/staying alive far more than (if they were at all) about relative luxury. Just look how many men and women are quite satisfied with living on benefits while doing nothing to earn them or improve their lives by actually making a effort and i think that is where we will find the missing part of the puzzle.
Primitive instinctual desires developed to aid in gaining the basic requirements for simply surviving are no longer activated by provisioning because the basics of survival for her and her offspring are provided in abundance due to (relatively speaking) poverty in a modern nation being luxury beyond imagination to those instincts leaving just the desires for "primitive instinctual highs" and "social dominance gains" as the things that activate what is fundamentally a primal survival instinct.
You illustrate it perfectly here when you point out the seemingly contradictory behavior, but its not contradictory and makes perfect sense as the instinct is for basic survival provisioning not modern luxuries.You will often see multiple women paying for Leroy's food, his car payments, etc. to be around him - in fact, the opposite of resource provisioning.
What we have is a primal survival instinct now only activated by "primitive instinctual highs" and "social dominance gains" and not activated by provisioning due to the relative luxury of modern life. Because with all basic provisions gained for free provisioning (as the instinct defines it) has become valueless and to such a psyche provisions are easily traded for the 2 things still seen as valuable by it.
So maybe we have 2 kinds of hypergamy, the first is the older primitive one based on survival instincts that we are discussing and the second is a more modern one less instinctual and its concerned with greed, selfishness and luxuries gained with as little effort as possible...by manipulating men.
Oh hi by the way its been a while![]()