1. The quality of the food has been declining, leading to a decrease in customer satisfaction, which in turn has led to a decrease in turnover.
2. Competitive pressure from buffets in star hotels, leading to a decrease in customer traffic.
3. The restaurant's operation was greatly impacted by the epidemic, and eventually it was difficult to maintain operation and closed.
This is a complex issue, in which there may be other reasons, such as rental pressure, management problems, etc., which may have affected the operation of the restaurant to varying degrees.