Amazon created its ECS (EC2 Container Service) system for launching Docker containers directly in EC2 for two reasons. First, to bring a new feature to its user base, but also to take on competitors like Google’s Container Engine.
That dynamic hasn’t changed much. Since the initial release, Amazon has ushered forth a new wave of ECS features focused on deployment, management, and configuration. The upgrades result from demands by Amazon’s users — and possibly pressure from third-party container management offerings that run on AWS.