First, "biological reality" isn't what you seem to think it is. In some species mates are chosen based on who's the best singer, or who has the best dance moves. ;)

But let's talk about humans, the most adaptable of the bunch.

As female opportunities have grown, they're reduced the need for the dominant consideration to be "big strong man who protect me"; or "who has the most money"; to "who will make me happiest."

Or to put it another way, since you want to define happiness in an anthropological sense, with physiological and safety needs now capable of being met on their own, modern women have moved past the base of the triangle in Maslow's hierarchy of needs.

They can now reach for love, personal self-esteem, and self-actualization. And those are NOT trivial needs.

But don't take my word for it. Read, say, any of Jane Austen's books. They were written a couple of centuries ago, and yet pretty much every one is a scathing critique of a system that forced women into marriage as their primary means of securing financial stability and social standing.

And sacrificing happiness in the process.

It's not a new thing.