Humans do not act on biological impulses and instincts alone, that's why your train of thought is not much aligned with reality.

Women rationally know that contraception pills exist and are effective, meaning the choice of getting pregnant is in their hands; (promiscuous) sex apparently has no consequences. This informs their actions.

That might be true. But at least what you describe is not my experience. All women I know want serious relationships, not one-night stands (Belgium). Maybe in your part of the world or generation that is different.

It does: women has always has dual mating strategy (find a sexy partner to have a baby with and a sucker who will take care of the baby...if she's lucky it's the same person, but quite often that's not the biologically optimal behavior).