It run's on all major cloud platforms, VM environments and bare metal. Supported by every major player except Amazon (for obvious reasons, why would they want to support something that makes it easy to migrate away from them?)
AWS, Microsoft, and Google.
When AWS first started, it was EC2 and S3, so the model was about VM without worrying the bare metal. But as the platform continues to grow to challenge its competitors, the platform will begin to add more services which are only available and are proprietary to the its own platform.
Yes. Google's strategy with Kubernetes is to commoditize the cloud - making them all functionally interchangeable. Write to Kubernetes, and your app runs on AWS, GCE, Azure, etc...
They are betting that they can deliver raw CPU cycles, network bandwidth, lower latency etc. - better/faster/cheaper than their competitors.