Here are articles from Statista that may be worth a look by some sellers here. The first shows that buying second-hand merchandise is on the rise in the U.S. and elsewhere. The second two focus on the sale of second-hand clothing, specifically.
I think that buying second-hand merchandise is on the rise in the U.S. and elsewhere, especially since eBay added that "Find Similar" link to everyone's pictures. Coincidence? I think not.