I don’t see Fargate as a competitor to Kubernetes in a functional matter. Fargate is filling the void for running containers outside a cluster, whereas Kubernetes (and ECS) are primarily focussed on clusters / namespaces with services inside. On top of that, Fargate is really expensive to keep running continuously as mentioned above.

I actually would like to think that the adoption of managed Kubernetes in AWS is a move Amazon did in response to some of the players switching to the Google Cloud stack for their managed Kubernetes services. I really like the move Amazon made though. For us, both ECS and fargate are just way to tied in with the Amazon ecosystem.