AWS and other cloud provider provides far more reliable and simpler features/toolkings than k8s. For teams that's serious about building services on the cloud, having k8s to take over certain area of orchestration make sense, but the "operating system" K8s provides is just a tiny peace of the overall infrastructure.
The meaning of "app" on top of these two operating system abstractions is entirely different and the comparison probably doesn't extend beyond this. From a computing stack standpoint though, it makes sense.