Hrm. No one has mentioned the decline of middle class wages.
I remember in the … late 70s/early 80s my mother would drag us to the mall nearly every weekend. She was there to buy clothes. She always wanted something new and she wanted to try on at least a dozen items before buying one or two. I was thrilled when I was old enough to go off to the record store and/or hobby store while she did that. Earlier, I begged to go the the toy store, but was typically refused. Later, I was at the book store getting paperback scifi.
I don’t think people have as much disposable income as they did then. I don’t know many people who can buy as much frivolous stuff as my folks used to. I guess I could technically buy stuff all the time, but I want to save fore retirement. My folks had pensions. I have to put it away myself.