Better alignment of incentives. The retailer (especially for a huge company like Amazon) has more resources to pursue manufacturers with defective products, the

Better alignment of incentives. The retailer (especially for a huge company like Amazon) has more resources to pursue manufacturers with defective products, they have more information about their supply chain which is useful for issues with international manufacturers, and putting the onus on the retailer encourages the retailer to not allow shoddy or counterfeit products into their marketplace.