[chrislaco]

I take a small issue with "now all these people use a standardized Dockerfile"

And many folks don't, because the amount of unreadability from having to concat 20 statements in a && fashion to cut down layer size gets out of hand. This leads to folks then having to use scripts to clean the layers, which leads to reuse in things like Packer, which leads to even more problems when the base image changes culturally.

I'd also argue the that it's a matter of familiarity. Every time we change the base image culturally, we have to retool for a different method of making the things in it (apt/dnf/yum -> apk), so while large distro images are bad, they're familiar and predictable (with a mature package set and releases) to what we're used to doing on servers.

Or folks use another tool to abstract that (like Ansible or Chef), which brings us right back to not using Dockerfile.