This question isn’t really MLOps related because it can be generalized to many fields. Proprietary container management tools like ECS, Docker Swarm, and Hashicorp Nomad have weak open source ecosystems. While running most applications starts with the container, everything around the container requires many additional layer. Examples are config for autoscaling and connectivity between micro-services. The MLOps industry, like most others, has organically picked the Kubernetes ecosystem.