I think this is the analogy folks who really want to hang their hat on K8s would like to force. It feels familiar, and it helps justify the tremendous personal investment of time it takes for running your own K8s cluster with high uptime. The usual adage that "free software is only free if your time is of no value" really does apply here.
Assuming you're writing code that lives happily inside of a container, and assuming that you're not taking advantage of anything else AWS has to offer (which is increasingly improbable), moving from ECS to EKS or GKE isn't a big deal if you need the additional configurability that real Kubernetes offers.
Personally, I like running things on Fargate-style containers so I can keep things as serverless as possible.
Assuming you're writing code that lives happily inside of a container, and assuming that you're not taking advantage of anything else AWS has to offer (which is increasingly improbable), moving from ECS to EKS or GKE isn't a big deal if you need the additional configurability that real Kubernetes offers.
Personally, I like running things on Fargate-style containers so I can keep things as serverless as possible.