It's hard to find the right words for this, but I would sincerely reevaluate your perspective.
A surprising number of people thrift / buy used clothes. Between thrift stores and consignment shops, more people shop there than Department stores (30% vs 21%).
It's currently popular among younger people as a push against "fast fashion". People want clothes that are unique and affordable, and their only options are thrift stores or color blocks from Uniqlo.
This is the "kind of person" who buys used clothes:
Fast fashion is likely undermining used clothes, since they degrade quickly to not being wearable, but still have the same landfill degradation problems as other textiles.