I think the world has changed .
Three elements of that change:
The advertising industry realised that under 16s are a major market for fashion items including clothes, cosmetics, body care products.
The pharmaceutical industry (that created the opioid disaster) saw a way to push into that market, and assorted medics and therapists followed them.
The constant, highly visual but also highly faked connectivity that smart phones have facilitated.
The child and teenage market thing really took off from the late 1980s - more money, more fast fashion. I remember the first time I noticed a group of primary schoolchildren where the girls all wore pink and purple jackets and the boys were all in blues or grey. Not a school uniform, just the manufacturers push - 1993.
The pharma thing has intensified since the hugely lucrative opioid market began to be regulated - gender related medicine (and how you medicate for a feeling baffles me) is the nest big thing for them.
I don't know what mobile phone apps have been the real trigger for the worst of this, but I hear 2012 being identified as a year that saw a big uptick in child and adolescent mental health problems linked to phone use - not sure why? I remember the pro-ana sites being a concern well before that, but think they may have been accessed by home computers rather than by phone. Prescriptive gender stereotyping seems more of a smartphone thing.
But bottom line is, the world has changed for young people since the 1990s and before, and not in a positive way.