Desired characteristics in models aren't necessarily intuitive. Example: squarish jaws can be sought after because it's more androgynous and thus covers a larger potential consumer base.

Beauty's subjective, of course, but media agencies push the agenda that X, Y, and Z are "the most beautiful" women in the world so everyone follows along because it would be wrong to go against the majority, after all.

It also depends on who's in charge. If a lot of gay men are ruling fashion, they're probably inclined to different standards than John Doe. Same for women.

I don't find many mainstream models attractive, Chrissy included. But voice that and depending on your gender and crowd, you'll be called blind or a faggot.