@valleyforge What happens when the management no longer thinks the company's viable, or the proprietor wants to retire, etc.? Selling to a competitor allows the business's customers to keep receiving whatever service it had been providing.

For example, in aviation: when US Airways bought out the bankrupt American Airlines, it inherited the obligations to transport AA passengers who already bought tickets. When Thomas Cook went bankrupt without a buyer, hundreds of thousands of passengers just lost their money (technically, they held unsecured debt for whatever refund they were due, but that was effectively worthless, given that the airports secured their debt by impounding TC's assets), and many were stranded abroad.