Why do some girls with a high SMV, settle with men with a low SMV — when they are still relatively young?

I would not say this is a common occurrence, but it’s something I notice every so often.

It involves girls with a high SMV, settling (marriage, children) with men who have an incredibly low SMV — when they are in their early to mid-twenties.

I believe that the majority of women’s SMV is generated by attractiveness alone, whereas; calculating men’s SMV has more branches (attractiveness, physique, career, social standing, social skills, experience, alpha traits, etc.).

Bear in mind: these are not girls who have hit the wall, who are tying down a BB after riding the CC for years. They are not damaged goods. More so, it is their first (or possibly second) relationship.

The men may have some resources (such as a steady, above average paying job); but they often lack social skills, do not take care of their appearance (terrible sense of style, overweight).

The disparity can often be incredible.

I know plenty of girls who’s first boyfriend’s had low SMV, but once they discovered their own SMV (through being approached by more experienced, better looking men), and understanding the power they had over men — they did not hesitate to ditch their childhood sweethearts and never look back.

Why do some settle, when they could do so much better? Is it a case of the girls having incredibly low self-esteem, and not realizing their SMV — such as a single girl of similar attractiveness? You can't miss what you have never had. Maybe they feel content, and have no confidence in jumping ship when they have always had the upper hand in the relationship, and are fearful of the unknown?

Any insight is welcome.