I think that there are some general principles that explain this sort of thing, but that can also be misunderstood.
1. Clothing styles that teenagers can get away with look absurd and unflattering on people who are well into their physical maturity.
This is true, but in affirming it one may neglect the fact that a lot of the clothing fashions of young people are tacky and ridiculous. (I have my own pet examples, but I won't state them here, as to do so would distract from the main point.) They do not look good on young people: they just look less ridiculous on young people than they do on older people because we expect young people to make some bad choices in fashion. Their tastes are immature and they need to distinguish themselves from their elders. We expect better judgment of those who have been adults for a good long time: that is why the clothing of young people sometimes looks ridiculous on them.
2. The disparity between what a teenager can wear and what an older adult can wear is greater for women than it is for men.
Yes: but the fact is that there is far greater diversity of style in women's and girls' clothing in general than in men's and boys' clothing. Men can get away with wearing the same kind of casual clothing all their lives because there are certain articles of casual wear, like blue jeans and a T-shirt, or chino trousers and a polo shirt, that have remained in fashion for decades. Women's fashions, casual and formal, have far greater diversity and change far more quickly, so a woman is more likely than a man to make the sort of upsetting discovery that Dragonfly reports.
For my part, I forsook blue jeans in favor of grown-up clothes when I was in my early twenties, and since then I have only had to make small adjustments for changes in fashion, such as the width of collars and neckties.