I think the marketisation of 'pink' for girls really began in the 1980's......before that it really wasn't a big thing. Aligned to that was the marketisation of childhood itself, and just about everything else - after the liberalisation of 'the market' and 'the city' under Margaret Thatcher.
Britain really seemed to embrace American consumer culture then. The credit card became a thing......and success was seen as owning lots of consumer products, expensive watches, designer clothing, foreign holidays....even the 'plebs'.
I think that is when more rigid categorisation of girl toys/boy toys and the 'girly pink' thing took off too. I was born in the 60s and grew up in the 70's and this pink business just wasn't a thing, and I had short hair at different times during my childhood, and then again at 12 ( and still do now) when I got my ears pierced for my birthday. Having short hair felt liberating.
Disney became a huge marketing machine...pushing gender stereotypes and imagery and all of that princess guff. My grandmother called me her princess when I was a child, but she didn't mean in in that way......all fluffy and dressed up as Snow White. You can guarantee that whenever there is a World Book day at school now - half the girls will be dressed as Disney princesses.
Toy stores have boy and girl aisles - with certain toys designated for boys and others for girls.
Some female hair stylists simply no longer work with short hair; they don't know how to cut short hair on women. My daughter experienced this when taking her daughter ( my granddaughter) to get her hair cut short when she was 6 ( she'd asked for short hair). The allocated stylist freaked out.....and the owner of the salon had to do it.