> There isn't enough stock for them to close their position
Tens of billions of dollars of GameStop have been bought and sold over the past few days. If you can buy GameStop to go long, you can buy it to cover a short.
Note that there isn't a limit on rehypothecation. A share sold short by Bob can be used by Anna to cover her pre-existing short.
Yes, even if it's the same share that Anna sold to Bob short in the first place. That's how you get short interest > 100%. The market doesn't care, it only cares that a share was sold from Anna to Bob and then from Bob to Anna. The individual shares are completely fungible. (They don't actually exist, they're just numbers in a contract.)
Tens of billions of dollars of GameStop have been bought and sold over the past few days. If you can buy GameStop to go long, you can buy it to cover a short.
Note that there isn't a limit on rehypothecation. A share sold short by Bob can be used by Anna to cover her pre-existing short.