I have nom doubt that there are legit use cases for something like k8s at Google or other multi-billion companies.

But if its use was confined to this use case, pretty much nobody would be using it (unless as a customer of the organization's infra) and barely would be talking about it (like how there isn't too much talk about Borg).

The reason k8s is a thing in the first place is because it's being used by way too many people for their own goods. (Most people having worked in startups have met too many architecture astronauts in our lives).

If I had to bet, I'd wager that 99% of k8s users are in the “spin a few containers to run your web app” category (for the simple reason that for one billion-dollar tech business using it for legit reasons, there's many thousands early startups who do not).

The legit use case for companies like Google/Amazon etc is only to sell it to customers. None of these companies use K8s internally for real critical workloads.