It's the other way around. The public offerings were built and only much later were they used internally, at least with any widespread adoption. They are many

It's the other way around. The public offerings were built and only much later were they used internally, at least with any widespread adoption. They are many AWS products that are a derivative or variation of internal tools, but they are effectively almost always rewrites with significant changes. The dogfooding comes much later. Source: I once worked there while they were migrating workloads to these AWS systems.