As a side-effect this will also increase the prices of the cheapest clothes available on the market, and as such would in effect be a regressive tax.
First, this will revive the second-hand market, which is where you got clothes for cheap in the past.
Second, The absolute price for a clothing item is not really relevant without considering its lifespan.
A metric of sorts "square meter of fabric per year" per capita would be more useful, and the super cheap clothes don't look good at all here. Even poor people will not wear a super cheap shirt for years, when other people throw it away after 2 weeks.
With the exception of children's clothes. These unfortunately get hit with all issues: 1. Kids are more active and will stain/tear them more often than adults. 2. They grow out quickly, limiting initial lifespan. 3. Due to point 1, it's hard to resell things past the baby stage.
Also, second-hand markets here are already large and could become even larger. Searching for "used kids clothes" on Ebay shows 350k results.
New cars are disproportionately expensive too. Shrugs. I think it's okay that not everyone can afford everything new, as long as they can afford enough to not be further disadvantaged.
Since the 50s we've seen races to the bottom with clothes, homeware, furniture. It's all lovely shiny and new and when we've decided we need to change it, we burn or throw into a hole in the ground. Fashion has invented its own mechanisms and sub-industry to make sure things aren't just disposable, but that people want to throw them away. It's disgusting.
We don't do that with cars. We demand that cars are serviceable. Older cars doesn't carry stigma (unless they're clapped out). We need to start demanding the same from everything we buy.
Create a standardised quality ranking of cloth longevity/repairability and force the manufacturers to display it prominently and accurately.
Why would the law prohibit me from buying a $1 shirt that lasts 1 week and instead buy a $50 shirt that lasts a year?
The effect will be identical to that achieved by reusable grocery store bag laws. Tons and tons of extra waste, as well as taxing the poor more.
Because society has to bear the cost of the environmental degredation of manufacturing and disposing of that $1 shirt. The price signal doesn't include the externalities.