I work at a place running a million containers deployed in all 3 (Azure, AWS, GCP). I can assure you they are radically different; autoscaling works differently, the load balancers work differently, the networking infrastructure is completely different, the failure modes and limits behaviors are different, the instances perform differently, observability is different, and they all suck in unique and different ways that we discover on a daily basis. Shit even AWS can't keep their regions consistent; each region has different products and features and they fail in different ways.

If you are the one maintaining it it's a full time job handling all these edge cases, it's completely miserable and I wouldn't recommend it to anyone.

The essential ideas that Kubernetes exposes concretely are invariant across cloud providers. There absolutely are nuances and quirks that are different for each cloud provider, and unique for the workload you have. However, those same ideas also act as a kind of mental framework in which these quirks can be understood from. It isn’t as if those quirks are randomly there, unconnected to anything, and therefore not part of a coherent design.

For example, the consistent use of labels as a way to identifying groups of resources that need to coordinate with each other is very useful for any distributed system. I find myself looking for them in say, CI/CD systems (in the form of agent tags), or at the application level in say, matching players to game servers.

Until you want to scale and optimize resources.

I enjoy working with Kubernetes, but forcing a complex domain into something legible is a recipe for catastrophe. There are quirks, across cloud providers, and this is just another day in Ops, with or without Kubernetes. (See: https://www.ribbonfarm.com/2010/07/26/a-big-little-idea-call... )