Subway has always had a poor reputation as a franchisor. If a person buys a franchise that does well, Subway might sell a franchise to a different franchisee directly across the street.
I personally know of a couple who put a large restaurant in a convenience store and subway put a store in the new wal mart 500 feet away from them.
I know of one shopping mall that has a subway in the wal mart and one right across the lot in a strip mall.
I don’t have a clue how they make any money.