Why ask these questions only as they relate to women and motherhood? Why haven't men being presented a false promise that value and purpose is derived from work? Being a father without a snazzy career is equally (if not more so) frowned upon by plenty of people these days. I don't think that stigma is healthy, either. Why do men have to emulate other men to be "valuable"? Why do men have to avoid emulating women to be "valuable"?
> Couple that with the fact that depression is most prevalent among childless women in their 40s
I don't know your source for this but you should at least consider the possibility that women, particularly women with financial resources (childless women in their 40s, for example), are significantly more likely to seek mental health treatment compared to similarly situated men. Correlation is not causation and more women being treated for depression does not necessarily mean more women are depressed.