Willingness of men to “marry up” MISMATCH w unwillingness of women to "marry down"

This paragraph made me wondering about the relationship between DS and his GF.
DS once mentioned that he thinks his GF is very smart, so he likely thinks he marries up in this sense. Not sure how she thinks of him in this regard though (However, I heard from DS at one time that almost the scores of all the standardized tests they have taken so far are almost exactly the same.)

It seems she might be more organized but he likely has more “outside” interests (e.g., cooking?) which have nothing to do with his career. There is a slight chance that her side of family may think DS could be slightly too “relaxed.” (Gap year and all that.)

Socio-economically, her side is likely higher according to DS’s descriptions a long time ago even before they had got together as a couple.

Hmmm…we have not been made aware of the size of her student loans yet. Don’t tell and don’t ask here. However, I would be somewhat surprised that they have not touched on this unromantic topic by now after almost a year – but how would the parents know?! I guess each will be responsible for paying off his/her own student loans.

No divorced parents on both sides.

Her side of family seems to be much larger than our side, especially, having a larger extended family.

Is the size of indebtedness (including the student loans) on each side a factor in determining whether a person marries up or down?