I've seen the numbers while I worked at Amazon. Its interestingly AWS that can't lose Retail as a customer.

Retail can very easily afford the AWS bill and is actually currently still getting ripped off by AWS. Retail really should build its own infra again (or at least use it as a negotiations tactic with AWS). It could easily save 90% of its infra spend if not stuck on AWS (including the internal rates it gets) right now.

Why build their own, I bet GCP or Azure would give them a crazy good rate :P

Could get a better rate – maybe. Could save 90%? I don't believe that.

That sounds like they are manipulating the numbers to make retail seem less successful, and AWS more successful.