It wouldn’t take you three to four weeks to rebuild a critical system, would it? But that’s how they do things in the National Health Service in the UK. Doctors and hospitals have been advised that the central patient record system is offline due to a ransomware attack and will not be back until sometime in September. In the meantime, doctors will have no access to their patients’ medical histories and will have to keep notes on paper or in Microsoft Word on their laptops.
As a national health monopoly, the NHS will not be going out of business. But a private company that lost its manufacturing, logistics, or service management system for a month would be finished.
You do everything you can to prevent bad things from happening. But have you also planned contingent action in case something terrible does happen? The NHS hadn’t.