That's going to be true no matter which cloud provider you choose
My company provides services to fortune 100 companies, and we host literally petabytes of data on their behalf in Amazon S3, but we don't have offsite backups. We (and they) rely on Amazon's durability promise.
We do offer the option of replicating their data to another cloud provider, but few customers use that service -- few companies want to pay over twice the cost of storage for a backup they should never need to use when the provider promises 99.999999999% durability.
I don't know the data you're holding. If it is sensitive data, like customer anything, would it infact make sense not to have offsite backup?
Reasoning: Your contract with Amazon promises durability and I'm sure there's a service level agreement with penalty/liability clauses. By implementing a redundant backup, you're replicating something that you don't legally need to have, double-or-more due diligence on the offsite backup security/credentials, and in case of a failure of Amazon create a grey area with clients "Do you have the data, or do you not?"
In short, there could be a very good business reason not to do offsite backups.
Regardless of durability if you lose your customers data are you sure you will have customers paying you to keep you in business while you figure out liability?
In this case, it was not losing data, but losing access to data. The data was eventually restored. Lose customers' data could also mean losing the backup:
"We're sorry, the tape that we didn't needed to keep has been lost/zero-dayed/secondary service provider has gone bankrupt/Billy's house that we left it at got robbed." These must be disclosed to a customer immediately.
Minimising attack/liability surface is not only a technical problem, but a business one too.
For AWS it doesn't make a lot of sense to protect against AWS itself losing data since you're paying them a premium for that. Backups in this model would be logically separated so a user/programmer error can't wipe out the only copy of your production dataset.
It's just greed, not some wisdom. When data is lost - it's just lost. Maybe AWS will pay some compensation because of their promises, but money not always can solve problems of missing data.
My company provides services to fortune 100 companies, and we host literally petabytes of data on their behalf in Amazon S3, but we don't have offsite backups. We (and they) rely on Amazon's durability promise.
We do offer the option of replicating their data to another cloud provider, but few customers use that service -- few companies want to pay over twice the cost of storage for a backup they should never need to use when the provider promises 99.999999999% durability.