This is a long article. Still not done, but here’s another generalizable observation:

“A beauty ideal actually needs to be unattainable. If it were attainable, it wouldn't be useful for discriminating between the best potential mates, since all of them would have attained it.”

I think this applies to many virtues in many contexts, not just beauty/mating. For example, consider freedom. That is, freedom from coercion by others. Modern Western civilization is perhaps the freest in history. Yet I and others desire even more freedom. Even less coercion.

It’s perhaps comforting to realize that the ideal is approachable but unattainable. Believing the ideal is attainable leads to suffering—since every outcome will fall short. Believing the ideal is approachable leads to effort, improvement and (hopefully) satisfaction.