Look, WalMart took out most of it's fabric departments, then put a lot of them back in, even if in a limited capacity. They obviously see the value and profit of having a fabric department.
Most Wal-Marts have leased spaces already. Fast food, eye doctor, hair stylists, nail salons, etc. It's not much of a stretch to see a fabric store inside too. Probably depends on how much Joann's is willing to pay to lease the space. Let's face it, it all comes down to money.