How do you know it's "finished"? You could have said the same thing in 2006 and been completely wrong. What makes you think the customer front end of Amazon is

How do you know it's "finished"? You could have said the same thing in 2006 and been completely wrong. What makes you think the customer front end of Amazon is where the bulk of the engineering is? Edit: engineering and maintaining the infrastructure of Amazon compared Vs cracking a code in world war two seems like a strange comparison.