There are so many tiny little differences between the cheap shit at walmart, and the usual stuff you got off the rack about WWII.

Thread, lining, attention to details, fit, function.

One of the biggest things is clothes, today, are designed to look good on a hanger.
They are not designed to look good on anything but a super-model who is basically, built like a hanger.

I can show you all kinds of tailoring tricks to fit different women, and everyone one of them makes an item of clothing that slouches, puffs over, droops on a hanger. But they fit the woman. Look good on the woman.

And it is not just clothes, it is everything.
Things build a mm smaller... and so break more often. And lack of any good purchase for screws, the steel being a hair thinner, it is all snap together. Not repairable.

Although the metallurgy has gotten better, cutting a penny off of production means it is just that much flimsier.

Lastly, i must say, that there are engineers hired by big car manufacturers who's job it is to make the part last past the warranty period, and not much longer. These companies are probably going to die in this next depression... and they deserve it.