All chip + signature cards in the USA have a stripe too (excepting maybe a tiny fraction of retail cards). They have to, or something like 90% of POS will not accept them. Full rollout is going to take years. As long as there is a stripe and merchants accept the stripe, the stripe can be cloned. Yes, retailers who take the stripe when the issued card has a chip will be on the hook instead of the bank, but thieves don't care if the retailer or the bank pays.