There's risks and there's bankruptcy. If you feel like gambling then be my guest. What's the risk of your house catching fire? Are you insured? What are the risks of getting burgled? Your car stolen, a car accident? Are you insured?
What are the risks of having a bad health issue happen to you? Are you insured?
I'll bet that you don't know the answers to any of those questions, and yet, you are probably insured against all of them.
As for your question in more detail: it happens often enough that for me if you operate your business 'in the cloud' and you don't have a back-up of your data outside of the cloud to guard against catastrophic data loss due to either malice or accident that I'll happily fail you. Think 'sysadmin was depressive, wiped out company' (or maybe you let him/her go and they took revenge or any one of a number of other scenarios that would instantly terminate your existence online if you had not guarded against it).
Risk management is consequences * incidence versus cost to mitigate. If the cost to mitigate is negligible, the risk is measureable and the consequences are terminal then it is a no-brainer to protect yourself against this. At least one of my customers wished they had set up a backup facility for their critical data (too bad, end of story for them) and there is one published case that we all know about. That's two that you can count on and most likely other trouble shooters have similar stories.
I see catastrophic cloud data loss as having a much higher chance of happening than many other items on the list of stuff that I verify before greenlighting an investment.