We walked in to shop (not to eat) and the WalMart folks were busy redecorating the space to sell merchandise. We asked about it and got vague, nobody-tells-us-anything answers.
In my experience, businesses close when they aren't making enough money, period. So my conclusion is that this McDonalds outlet wasn't making enough money to cover the lease, pay the salaries and suppliers, and still make money for the franchise owner and McDonalds corporate.