I think one of the biggest reasons young people spend so much from experience is that the jump between being a broke “college student” to making salary-like income is that you feel “rich”.
I was used to penny penching when broke but once getting some money I never took account of savings. My mindset was that If I could survive off little then I could survive off a lot but the real change happens when you get tired of “surviving” and want to thrive.
But yes, lifestyle inflation is one hell of a drug.