Kubernetes can really help bringing more scalability. All you need is to rewrite your application (think microservices), reduce cold latency (get rid of anything VM based such as Java, or rewrite in Spring or Quarkus), use asynchronous RPC, and decouple compute and storage. Then you need an elastic platform, for instance Kubernetes, with all the glue around such as Istio, and Prometheus, and Fluentd, and Grafana, Jae…
Running a big Java monolith with 128GiB RAM footprint in Kubernetes works well. It's at its best when deployments are infrequent and traffic patterns are stable (or at least predictable).
If someone wants stateless microservices with immediate scale-up/scale-down, then that's more like a FaaS ("functions as a service") and they'll be better off with OpenFaaS instead of Kubernetes.