I don't have a horse in this race, but IMO the point is more about AWS-provided infrastructure that lets people scale more easily than otherwise possible; things like Elastic Map Reduce, S3, DynamoDB, SQS + SNS, RDS, etc are less-easily replaced by home-grown equivalents. There are great open-source solutions for every one of those things, but the point is having to not manage them.
If you're using the cloud as "just another data center", I feel like you're missing many of the benefits of software-defined infrastructure and disposable systems.