I'm totally agree with you, but at the same time, the idea where higher price = higher quality also hold true.
But it required experience and research to find this particular brand that offered better quality for their price.
Like I said, it's not
reliably true. There are expensive brands that suck, and expensive brands that don't. There's also the question of what counts as expensive or not, and what level of affordability those brands exist within. More importantly there are questions about the external costs- pollution, fossil fuel consumption, worker exploitation.
But the idea that "if you're an adult you can afford more expensive things and those things will be
'better because they're expensive'..." There's a lot wrapped up in that kind of statement. A lot of it is symbolic, not practical.
A practical concern is, "How many seasons will this item of clothing last, and how many times will I wear it? Can it be repaired if damaged, or will it be unusable?"
A symbolic concern is "does the cheapness of this clothing affect my image? Does the clothing have the appearance of cheapness, regardless of price? Does wear and tear or minor stains affect my image?"
Most of the time, fashion is symbolic. There's no law of reality that makes cerulean blue the color of the season, or herringbone currently "in trend." They are arbitrary qualifiers to represent social class and create consumer demand. Violating fashionability is
sign crime. And we know social class and consumerism are ethically abhorrent and environmental catastrophes. I'd rather commit sign crime than participate in environmental catastrophes.