If you're talking about some $4 item then sure. But most clothing on Amazon isn't $4. If you're buying $30 or $60 items then they are most definitely having them inspected.

Because it's not about $1.50 for inspection vs $0.52 to throw it out.

It's about -$1.50 + $8 profit = $6.50 gain for inspection vs. -$0.52 + $0 profit = $0.52 loss for throwing it out.

You're missing the entire resale price on the return. Companies aren't leaving money on the table. They are looking to maximize profit and minimize losses. In most places, sending resellable stock to the landfill isn't doing that.