Things will only have useful size metrics when the buyers want useful size metrics.
Men’s pants come with useful size metrics because they’re useful and we attach very little meaning to the measurement of men’s pants.
Women’s pants come with stupid size metrics because we attach a lot of meaning to the measurement of women’s pants.
It’s the same reason condoms sizes are all on the spectrum of large to extra large without actually providing a length and diameter.
When was the last time you measured your waist and then tried on a pair of pants?
Men’s clothing has tones of vanity sizing these days.
The cuts of fabric are cut with dies. A layer of fabric is place down and a press presses the cutting die down to cut out the shape. A cheap manufacturer over stacks how many sheets are cut at ones. Top layer is going to be bigger then the bottom layer.
I expect there is much more hand cutting going on than you realize. To have multiple styles and different cuts would require giant warehouses of dies. Those aren’t cheap and wouldn’t last long in a production environment. Any change would require a new die. The machine shop would need to be as big as the cut sew shop.
One skilled (or trained) operator can change from pants to shirts on a whim. You’ll notice almost all clothing is made in far off places where labour is cheap. Not to say there isn’t die cut stuff, but overwhelmingly the textile industry is hand made.
These things are how multiple layers of fabric gets cut.
It’s the same reason condoms sizes are all on the spectrum of large to extra large without actually providing a length and diameter.
In Germany the packaging indicates the [Edit: diameter half circumference] in millimeters ±2mm tolerance. Because, you know, size matters here.
Half circumference? Why?
(Yeah I zoomed in. It’s 52mm, which is fractionally over 2 inches)
The literal translation of what’s on the box makes it easier to understand:
Width of the condom when laid flat: 52 mm
It’s simply the easiest width measure you can do yourself.
So that thing is 4 inches across? Eek!
Edit: oh, you said “half circumference”. For some reason I thought that I read diameter.
It did read “diameter”. I remembered it wrong and corrected my mistake. Sorry for not highlighting the edit. I did so now.