I think it is what is “within reason” that is being discussed. In my opinion, that’s a personal choice. However, the social media aspect of it seems intended to emphasize the conspicuous consumption, which would not be the case if the child simply wore the dress to the ceremony.
I wouldn’t know a $1,000 dress from a $100 dress from a great find at the thrift store.
Our parish has discussed --- but not settled on --- an approved choice among 3 quite simple white dresses, similar to the range available for the school uniform.
One thing the parish did make a ruling on was "no make-up." It was turning into a fashion display, like those poor little tiara-crowned beauty contestants being pushed out into catwalk modeling pageants.
The mothers do this to them. Especially (I regret to observe) the Hispanics.
Our Asst. Pastor, Fr. Jesus, remarked that he'd like to put limits on the Quinceaneras as well, but he doesn't want to risk civil war among the moms!