An Earth with let's say 2 billion people at 2 set of clothes a year has considerably less environment impact that an Earth with 8 billion people averaging let's say 10 set of clothes a year.
The scale of deforestation to produce coton, and the boom of the plastic fiber industry are sizable phenomenons with huge visible consequences. Whole industries exist now in Bangladesh and Vietnam for instance that didn't exist 20 years ago. Factories, supply chains, large yearly resources consumption, etc.
These changes are visible anywhere from the shops of wealthy nation cities, to Google Earth timeline where you see entire forests disappear every year now (rate is exponentially accelerating)
How much of a problem is this actually? Eg what proportion of our overall emissions (or environment impact etc) are from the manufacture and supply of clothing? And how much extra is from 'fast fashion' vs a return to old fashioned clothing habits?
I just did a very quick search, and found eg https://ourworldindata.org/emissions-by-sector Their numbers suggest that cotton and clothing barely show up.
Do you have any idea how much of a problem so called fast fashion habits actually are? Same for the others?
Scale matters.