I agree with other posters, there has always been something that every generation has bonded over. Back in my day it was white musk from the Body Shop, coloured denim, Sun In and the like for the girls. Both sexes did the Kickers trend. Boys then moved on to Stussy clothing.
Difference now is SM and in-flu-enzers who have upped the marketing to the younger generation so the cost has exulted, but underneath it it's all the same thing.
It's not just girls... Boys have to have the latest labels (just bought my 12 yo SS Nike Air 270s at the weekend because the Jordans he had and then the Air Force Ones are now out and 270s are in, I just thank my lucky stars the old ones don't really fit well now as he's on a growth spurt so it was justifiable) and are obsessed with football, Playstation and Xbox gaming and I sometimes find it sad not to see them out socialising with their friends like we used to do, but rather logging on to 'chat' whilst gaming (on which they will spend the majority of their pocket money given half a chance).
However, as others have said, this is a tiny tiny snapshot of them and not their 'lives' as a whole, they are still 'finding themselves' for the next 8 years at least, in a world that doesn't make it easy for them, so let's cut them some slack! We need to give them enough space and freedom to find themselves, whilst setting the boundaries that allow them to learn it safely and in this world that is sometimes a bloody tough call.
My nieces and friends daughters love football (a couple are top players in the area), music (trumpet), art, reading, animals (wants to be a vet). None of them are purely vacuous as individuals.
Oh, edited to add, as for skincare, all of us probably could have done with learning to wear SPF containing products a whole hell of a lot sooner knowing what we know now though so some of it is actually beneficial.