Agree with others who say it's about products, expertise and pressure. In one of my clients there is a team which has four or five young women in it - mid 20s.
They come to work looking as scruffy as you like, no make up, unwashed, scraped back hair, tatty, unwashed clothes and one of them literally stinks.
Look at the pics they share on their phones from a night out and they are unrecognisable. They are all red-carpet ready, with ultra long, expensively coloured hair - highlights, extensions etc. Shellac nails are a minimum, eyebrows are astounding, tan is applied the night before and then topped up 4 hrs before the event. Getting ready for a big night out takes all day, which they get very stressed about. Application of make up alone takes an hour.
They all live at home and spend a huge percentage of their salaries on clothes and makeup. They all have waxing, mani-pedis and entry level treatments such as Botox, chemical peels and boob jobs.
They aren't stupid. Most of them are university educated and take the way they look very very seriously. What they don't do, is eat healthily or exercise properly. They rely on makeup and great clothes to disguise their lack of muscle tone and pasty, unhealthy skin.
I don't get it myself. I think they should get more balance. Smarten up for work - don't smell would be a start, and stop worrying about how to fit in all the time it takes to achieve and maintain the footballers wives look outside work.