Realistically I think it's probably targeted at anyone who's willing to [get someone to] spend money on it.

Conspicuous consumption has been a thing for ages, and it's always been about presenting an image as having enough disposable income to be able to buy these sorts of things. The fact that some kids have parents who can afford to lavish this stuff on them only adds to the mystique.

I'd argue that it's also inaccurate to characterize this as just a kids thing. Plenty of people my age and older dump money into brands like Rolex and Mercedes. The main difference I personally see is that the price tags are even higher, and the brands themselves turn over at a slower pace.

Conspicuous consumption started with the invention of Santa Claus. Rolex and Mercedes leverage the snob effect.

https://en.m.wikipedia.org/wiki/Snob_effect

It's way older than that. There are ancient Greek philosophers who seemingly devoted their careers to criticizing the phenomenon. I would guess it goes even further back, but, past some point, writing down one's thoughts on the subject wouldn't have been available to anyone who might want to write down their thoughts on the subject.