Had Carvel committed tortious interference with a prospective advantage?

For decades, Carvel sold its ice cream only through franchised stores. However, a decline in revenues caused the company to begin selling its product in supermarkets. That effort expanded quickly, but many of the franchised stores (franchisees) went out of business. Franchisees filed suit, claiming tortious interference with a prospective advantage. In particular, the plaintiffs argued that Carvel undersold them in supermarkets and issued coupons only redeemable there. The case reached New York’s highest court.