AWS and Amazon.com are so far removed from each other internally that these might as well just be two entirely separate unrelated companies in regards to something like this. It’s not like Amazon prime just calls over AWS engineers to build out their platform. They most likely use AWS just like any other customer would.

Also AWS is so massive. I can assure you no single person can get it all perfect. Not even an AWS employee. Honestly especially an AWS employee. They spend all day working on the backend so I would bet most AWS employees have far less exposure to using AWS than the customers do.

User error in configuration is inevitable. Mistakes happen.