Speaking as a former AWS Engineer, I disagree with the sentiment that they are able to glue AWS services together better than what a competing non-AWS company can do. Internally the use of AWS is subject to the same constraints and APIs you and I have.
Their competitive advantage is their captive customer base, which will much rather pay a premium to use an AWS-managed service than use another vendor.
Their competitive advantage is their captive customer base, which will much rather pay a premium to use an AWS-managed service than use another vendor.