Yes, bankruptcy is certainly a possibility, perhaps not right away, but conditions exist which, if not turned around over the next couple of years, could eventually result in bankruptcy.
I think they are hoping for a buyout so the big wigs can just cash out and/or focus on the new 365 stores, but who wants to buy an outdated 1980s business model? If no one offers to buy them, then they're expecting the 365 stores to be their savior and earn enough to save the entire company which is not realistic at all. They just took on 1 billion in debt to buy back stock (who does that benefit----shareholders only--it does nothing productive for the business itself).
Bankruptcy is embarrassing, so I think they want to avoid it if possible, but WFM may indeed have backed themselves into a corner. The ones at the top will save themselves when push comes to shove (they will still walk away wealthy even if bankruptcy is declared so don't think they won't do it if necessary). Take care of yourself and don't count on WFM---they don't care about you. Study what happened at Enron and other big companies that screwed over their employees and then watch for the signs and make your plans accordingly.