The infrastructure of many companies is not located here or may be distributed geographically. Its in each company's self interest to plan for disaster. And if they don't, their competition stands ready to fill the gap.
Of course, things like the power grid and water systems where there are no competing providers, those are more likely to leave people completely without service.
Even the incentives to be robust or even safe are greatly reduced. A company with a legally protected monopoly can even blow up half the houses on a street (as PG&E did in San Bruno) and all the rebuilt houses are guaranteed customers.
Systemic effects like prolonged loss of power or water have the greatest impact, and are also the hardest to plan for. It's really hard to work out all the consequences of unplugging the electric grid in Mountain View for a week, let alone when there's multiple other emergencies happening in parallel.
Of course, things like the power grid and water systems where there are no competing providers, those are more likely to leave people completely without service.
Even the incentives to be robust or even safe are greatly reduced. A company with a legally protected monopoly can even blow up half the houses on a street (as PG&E did in San Bruno) and all the rebuilt houses are guaranteed customers.