That will never change, because it's being driven by female intrasexual competition. Men simply don't compete with each other in the same way.
Couldn't it instead rather be signaling to conforming to the modern idea that child raising is an oh so important task?
I don't think it's so much that women are subconsciously setting the bar too high. Rather, as in any competition the level of the bar gets set in the aggregate. Some combination of the media and their social circle.