An important issue is how a business will survive with the short-to-medium term absence of a key person. For example, you may have only one salesperson who knows, after 10 years, everything about your product and clients. The absence of that person from the business could seriously disrupt revenue generation.
Unfortunately, the overheads remain and suddenly a successful business is running empty on cash flow and in serious trouble. There are insurance products that can be purchased to help protect the business from such an event.