No ECS is definitely not going away. Having multiple ways of doing something is not strange for Amazon, in fact its what you should expect from Amazon. Just look at how many different database options there are!

ECS will remain as the free option that is great for small workloads, and companies that are going all in on AWS. It has the tightest integrations with other AWS services.

EKS is a good option for companies that don't mind spending a little more to run the open source version so that they have portability or a consistent environment between their on-premise and the cloud. While EKS does integrate with other AWS services it has to do so through plugins and controllers that aren't quite as tightly coupled, since EKS is just the same open source Kubernetes that you can run anywhere.

The use and functionality you get from ECS and EKS can be quite different. ECS is tightly AWS-integrated, EKS is designed to be cloud-independent. You can pick between ECS and EKS based on your needs and use Fargate as the interface to either.

It probably won’t go away. They didn’t eliminate Cloud Search when they started offering managed Elastic Search, or SQS when they started offering managed Active MQ. However AWS will likely put resources into EKS vs ECS.

Why strange? Customers asked, AWS provided :)

To me, simpler is better in many ways. I'll stick to using ECS till I hit something ECS cannot provide. I'm yet to hear what could it be.

Most likely yes. They've seen the writing on the wall, that K8s has won. It will probably just be a slow deprecation like they did with Simple DB.