Meritocracy and slavery are not mutually adverse to each other, in fact they usually come hand to hand, since weaker/unfortunate people tend to get very low on the social pyramid in meritocracy.
And that creates a feedback loop, cause they can't get better education/nutrition if they are not...
Alright buddy, you got two options here. You can be a MILF, or you can be a Thot. Those are your two choices. Choose wisely. So what's it gonna be, huh? Huh? The MILF? (Mommy) Or the Thot (betch)
This is why harems are kinda bad, you either objectify your spouses or they objectify you.
There might be exceptions but keeping the balance for the relationship in the harem to be wholesome is definitely very hard.