From what I understand Lebanon's Bekaa Valley has been the source of many high-quality counterfeit bills (article here https://en.m.wikipedia.org/wiki/Superdollar ), so merchants' refusal to accept old bills is understandable.
Most of the stores I interact with accept it -as long as it passes a bill checker- but they take a commission -usually 4$- on it.
I don't think they'd take it at all if there was a risk to lose 96$ on it.
People who have access to a fresh dollar bank account[0] have the ability to deposit the old bill and then try to withdraw it again in hope of getting a new bill.
A couple of services spun up that take lower commission for bulk conversions e.g. 2$ instead of 4$ for each 100$.
