I disagree. Kubernetes came out of Google, but has exploded in popularity due to its capability (which comes with extreme complexity): it can scale to extreme levels, but wrapping your head around it requires far more time and trouble for your most basic apps. Thus, you see the software consultants race to become the next Kubernetes experts, since choosing to deploy it essentially requires that you have dedicated professionals managing it (as Google does).
Docker Swarm might be incomplete and missing quite a few features, and it won't scale to thousands of nodes with dozens of independent apps, but the use-cases I've seen are far from that. A single engineer can basically get a "good-enough" moderately scaled system going.
If you have Google-scale problems with Google-caliber engineers and SREs backing you, use Kubernetes. Otherwise, using something else (Docker Swarm "just worked" for the cases I've seen) is easier.