Seems to me that both you and the parent have points. There is plenty of examples to show that spending habits are skewed, however much of what you say is true also.
I would tack onto this the scourge that is credentialism that effectively forces kids to go into lifelong debt for jobs that demand levels of education far beyond what is actually necessary. That is an insane burden.
I'm in my forties and got to watch as politicians in the 90s offshored basically everything that wasn't nailed down and in so doing saw my future evaporate before me.
Add to this the floodgates were opened on mass immigration far beyond our capacity to build housing to cover it (this is in the UK) and housing inflation meant I was never in a position to buy a home on the wages the remaining job types could offer. As all of these factors have continued unabated, my kids are now in the position that they would struggle to be able to afford rent.
I don't see this improving without a major course correction and there is no political will to do it. I've my doubts as to whether large swathes of the public would either.