Docker Swarm Classic (https://github.com/docker-archive/classicswarm) is dead. Docker Swarm Mode is alive, and I know some people use it, but it's very niche compared to k8s.

As someone who interacts with k8s regularly, I often feel like there is a place for a simpler k8s alternative. But looking at history I see the attempts like Swarm fail.

What do you think played the decisive role in the k8s victory? Features, openness, extensibility, something else? And do you think if there is a demand for a simper k8s alternative or is it destined to repeat k8s complexity to be useful? If there is such a demand, where did Swarm fail in particular?