I've had another casual read through Book 8, I might get another Zeitvice section going.
In order to find your own hidden biases, just flip the genders and see if you'd come to the same conclusions: Would rare males be fought over by "desperate or evil females"? Would Eladrin males be seen as pricey trophy husbands? Would females be "even more expendable"? Would the sexual dynamics be similarly out of whack and young women fear not being able to continue their lines? If not, then you are just inserting your own human (more or less patriarchy-based) assumptions into your line of thought (Well, you could add that you don't need that many men compared to women in order to have the same number of babies, but still...)As for the aftermath. Eladrin women are now extremely rare. That makes them valuable. As I understood it some Eladrin women were able to leverage that value for political power or to keep their existing power and became the matriarchy. Whereas in other areas they sadly became a commodity fought over by evil or just desperate males.
And remember historically Elfaivar basically collapses. We know some women flocked to conclaves and lived in hiding but others would have been caught by clergy forces and seeing they are a value a slave industry does sadly make sense that it could come about as the internal value on Eladrin women gets revealed to the continent at large. Scarcity is a value all its own.
Now if you look at the men of Elfaivar we can see a utter despair take over them. The sexual dynamics are completely out of wack now. Males are even more expendable in society as they vastly vastly outnumber the women, the older men lost their wives and families while the younger men have no hope of continuing their line.