To make a manufacturer responsible for a defective product in contract, the consumer must sue the seller, who in turn sues their supplier, and so on back up the chain to the manufacturer. If at any point the next person in line turns out to be bankrupt, to have disappeared or to be insufficiently well-off or insured to be worth suing. There is no way for the last party sued to leap-frog over them to their supplier, and so the chain breaks and the loss lies with the last party sued.