S3 is advertised as having 11 9's. That means in the entire history of S3 they've only lost a handful of objects, and will continue to lose objects at this same rate.
Durability is about: "If I successfully store an object in S3, how unlikely is S3 to permanently lose that object because of storage failures?"
It does not answer: "Will I be able to access that object, after a rain of Shahab-1 or Shahab-2 burn all data centers in the 3 availability regions across which my S3 bucket is spread out..."
It's similar to any engineered artifact, like a skyscraper. They have a structural safety factor that defines their resilience to failures that the system is designed to tolerate, it doesn't make them immune to missile strikes.