Most interesting apps run as multiple containers (e.g., a database) and then you need to provision volumes for application's data and configuration files. It doesn't seem clear to me that this is a strictly simpler state of affairs than local installation.
The real wins from Docker (for this use case) are:
1. Docker is a better process supervisor than systemd and friends
2. Simple, fast deployment (no manage ansible scripts or rebuild/reboot a machine image)
I think helm (helm.sh) solves that problem. Helm is basically package manager of kubernetes. So to install any app, as long as there is a helm chart for that app, you simply do:
helm install myapp
and helm will install the app on your kubernetes cluster.
Right, but now you're running Kubernetes for a single server, which is the very definition of overkill. Installing Kubernetes isn't easy, at least not when you consider DNS, ingres/load balancing, logging, etc.
Really depends on the package. I’ve had programs that take about a day to install, because the source wasn’t really portable and I really needed to get it to build, and I’ve had programs that are just five commands and it runs. It’s more work if you get the source from upstream than if you get it from ports or Portage or the AUR.