I really don't know what other production methods you would expect to find before docker.. install scripts and READMEs is pretty much all there is or ever was for complex software with many interlocking components. I don't really think there's ever been a way to install an entire stack like that from a single apt command. It's always been bespoke scripts and procedures with a lot of manual steps.
What I expect is a list of dependencies I can install myself, instructions to compile the code, and a description of config files to write/edit, eg. to point the main software to its dependencies' URLs. Like this, for example: https://docs.joinmastodon.org/admin/install/
While a readable Dockerfile can work as documentation, there are a few caveats:
* the application needs to be designed to work outside containers (so, no hardcoded URLs, ports, or paths). Also, not directly related to containers, but it's nice if it can be easily compiled in most environments and not just on the base image.
* I still need a way to be notified of updates; if the Dockerfile just wgets a binary, this doesn't help me.
* The Dockerfiles need to be easy to find. Sourcegraph's don't seem to be referenced from the documentation, I had to look through their Github repos to find https://github.com/sourcegraph/sourcegraph/tree/main/docker-... (though most are bazel scripts instead of Dockerfiles, but serve the same purpose)
