Of course, if you had paid extra for the backups and redundancy, your data would survive.
So to address your original point, unless you are paying extra for redundancy, it is cheaper if you use a 4TB SSD at retail price as the original commenter discussed.
In this case AWS did not save you. AWS is supposed to be resilient against AZ failures within a region. Iran destroyed all AZs at once, so all the data was lost. If you had a hard drive in your office, either directly serving your project or as an off-site backup, you still have your data. In the end, was it worth paying several times as much for AWS to provide durability for you, only to have them lose the data anyway?
it is advertised as eleven nines durability, however. That is better than anything you can build yourself, so if true, the best backup for your S3 bucket is an independent S3 bucket
Of course, if you had paid extra for the backups and redundancy, your data would survive.
So to address your original point, unless you are paying extra for redundancy, it is cheaper if you use a 4TB SSD at retail price as the original commenter discussed.