The experience of hosting and scaling Amazon may have informed some early AWS thinking but AWS was not built specifically to host Amazon and Amazon was never the primary target customer. This is evidenced by nothing more so than by the fact that despite Amazon's prescriptive initiative to move to AWS being well over 5 years in[1], much of retail & digital still runs on Oracle, dedicated HW, and bespoke internal services.

To make the statement today that Amazon "probably still is" the primary target customer betrays a lack of understanding of the scope of AWS and IaaS in general.

[1] It might be even 8+ years. I don't recall when it officially started so using 5+ as a very conservative estimate.

When you work on a product that has both internal and external customers, there are two possibilities:

- the external customers get priority because they're real customers that pay real money.

- the internal customers get priority either because they're the "real" business of the company or because they have the right connections

Amazon uses a very tiny fraction of AWS, but I'm willing to bet that their bug reports and feature requests are accorded a fairly high priority.