What's stopping the price from being extremely low? Plenty might pay $1 to take a bundle of 1000 items of clothing, pick through it and find 20 items they like, then destroy the 980 other items.
Also if someone is buying new goods for pennies on the dollar, I'd expect them to find some value in more than 2% of the stock.
It's 980(x+y) instead of 1000(x)
I have no knowledge of the tradeoffs, but I might also imagine that the method of destruction could be worse: incineration vs landfill vs thrown in the ocean, etc