Google has to support Google, Youtube and many of the most resources intensive services in existence on Earth. They needed to be "efficient enough" to operate that, meaning incredibly efficient.
Amazon runs nothing, it's an outsourcing firm. They needed to make services "good enough" to be sold. If a service is somewhat inefficient, it just charges the clients more to cover the costs.
Technologies reflect the business they were created in.
Agreed, and I work on Google Cloud. We may have different styles and core businesses, but I wouldn't say "eBay ran nothing" either. Logistics alone is a super fascinating space!
You do realize the way most services get into AWS is that they're first built in the retail side of Amazon (without any thought towards AWS) and then once people realize it's effectively solving an actual problem, it's rebuilt for AWS. Having to support Amazon retail is a pretty demanding stress test -- I'm not sure why you're getting this notion that Amazon doesn't run anything. I should think handling Black Friday alone would count for something..
That is something of a myth. AWS was created and evolves completely separately from retail, which didn't really use it in anger until 2010ish. Retail is effectively a large customer to AWS. They're very good at watching what customers are doing in general.
No one is saying amazon doesn't test their stuff. The argument here is that Google is inherently a more technical company, which is a fair comparison. Their products are more technical. Ad Sense, Gmail, YouTube are incredibly technical products due to their scale, and the argument here is that nothing of similar technicality exists in Amazon's core business, which I think is totally fair.
Amazon runs nothing, it's an outsourcing firm. They needed to make services "good enough" to be sold. If a service is somewhat inefficient, it just charges the clients more to cover the costs.
Technologies reflect the business they were created in.