Nigel, while the idea of "pretty power" being something women deploy among women, is relatively more visible in the west than it used to be, it's always been here to some extent. I attended 6 years of all-girls convent school, and if a girl over age 12 showed up for school without makeup she would have been bullied for years. We (unlike the boys at our brother all-boys school) were issued uniforms, supposedly to dampen competition over clothing. This lead to insane competition over socks, in terms of color, style and coolness.

One of the first places I noticed this emphasis on being beautiful for other women in adults was on the TV show "Botched" where plastic surgeons repair bad plastic surgery. The end of the episode is always a reveal party, where the contestant (usually a woman) shows off the results to her nearest & dearest. More often than not, it was all women. It a man was present, it was at least as likely he was the contestant's father as husband.

In Islamic cultures, women displaying beauty for women is much more common, for obvious reasons.

I must also note that a man not noticing every tiny detail can be comforting. If my husband doesn't notice I lost 5 lbs, he probably won't notice (or complain) if I gain 5 lbs.