Not OP and I don't do K8 in production, but I understand their complaint. You couldn't eg. deploy a game server easily.
They typical "web app" flow is Client -> ReverseProxy -> StatelessApp -> DatabaseWithState and back. The typically expectation is HTTP requests that aren't "long lived". Even running a database would be harder since you need to consider where the storage of the content is going (you'd want backups and snapshots etc) and how it'd get there. If the StatelessApp goes down (or you need more), you just add containers.
One example that wouldn't work well on k8 that I'm sure isn't very common is like a Minecraft server. It is a persistent TCP connection to a server that reads writes data to the FileSystem.
They typical "web app" flow is Client -> ReverseProxy -> StatelessApp -> DatabaseWithState and back. The typically expectation is HTTP requests that aren't "long lived". Even running a database would be harder since you need to consider where the storage of the content is going (you'd want backups and snapshots etc) and how it'd get there. If the StatelessApp goes down (or you need more), you just add containers.
One example that wouldn't work well on k8 that I'm sure isn't very common is like a Minecraft server. It is a persistent TCP connection to a server that reads writes data to the FileSystem.