A very generous and thoughtfully worded reply. Very grateful to your kind consideration of this subject.
It's incredibly complex and a lot of the evidence is circumstantial and layers of cultural cruft have certainly confused things but I'll say this --
People in the past didn't do things because they were stupid simpletons relegated to history books, they did a lot of things for real reasons and if we were born in those days we'd probably see the truth in spending a third of our income on clothing befitting our rank.
We ought to know by now the difference between an intractable argument and one we just can't understand yet, we seem to believe just because we can't understand something it can't be understood.
In my view people back then were very much worse off and struggling much more between the throes of life and death with sincere passion.
Having good clothes actually somehow conferred an advantage to the wearer that went way beyond societal perception or even shallow cultural biases to the core of their ability to live day to day.
You'd think we would've invented fast fashion earlier, but we've been wearing all sorts of costumes for millennia.
In the modern age our vehicles and electronic devices have taken over the cultural status symbolism perhaps but we've let our clothing sense lapse dreadfully into what I consider neo-renaissance pomp mixed with dark ages peasantry.
Anyway tl;dr - people in the past were struggling to survive yet still found some reason to invest a lot of their income in clothing.. Maybe there is something we've missed?