But, if they were going to find a buyer they probably would've found one already. They certainly will either have to have one before the open on Monday or it's not happening. The assets of the bank become more and more toxic as time goes on (this happened with Lehman Brothers) and if someone swoops in today, on Saturday, then it's not too bad. But if it sits a week and no one wants to buy it, if someone buys it next Saturday now that bank looks like a fool and people are going to question the deal
If they don't have a buyer, depositors are taking a haircut. Maybe they will get 100% of their money back in actual dollars, but they will lose via time--the FDIC will either liquidate the assets or let them mature. If they liquidate, they will take an immediate loss. If they wait for them to mature, then sure in 10 years everyone gets their money but Time value of Money is a thing and being made whole 10 years from now is not being made whole