K8s is doing distributed OS's on easy mode, supporting basically ephemeral 'webscale' workloads for pure horizontal scaling. Even then it introduces legendary amounts of non-essential complexity in pursuit of this goal. It gets used because "Worse is better" is a thing, not because anyone thinks it's an unusually effective way to address these problems.
I see K8S as Application Servers for everyone, with containers replacing EARs, it certainly gets some WebLogic/WebSphere vibes when looking at those yml files and how we used to setup an Application Server cluster.