I wouldn't expect your local mexican restaurant to have an emergency stockpile of ventilators (as handy as that may be right now..) but I would expect most clever small businesses to have resiliency by keeping cash on hand, operational flexibility (can they switch to a to-go model?) and not over-expanding.

You can't prepare for specific black swans, but you can generally structure things to be more or less resilient. It's not even impossible for small businesses to gain during this time - my local wing spot is doing crazy good business because they've converted to to-go orders amazingly intelligently (curbside delivery, easy to get orders, high order accuracy, and delivery area is well managed by multiple employees).