> Takes a few minutes max per machine (plus maybe package installs like zsh if it's not there already).
Assuming you have internet and can access GitHub. Setting up internally accessible repos for that or bake it into an image is its own excercise, which you'd have to setup again for every site and isn't there on day 0.
Even so, "a few minutes per machine" builds up quickly if that happens multiple times per day and new airgapped sites are a regular occurence. That's not including the possibly larger cost of context-switching to "customization mode" for every setup.
I do have a few dotfile customizations I carry around for sites/boxes I bother enough with but at this point they're cut down and familiar enough that it takes me a few seconds to put those in place manually from memory and dist defaults.
Minimal .profile:
VISUAL=vim
EDITOR=vim
tmux and some other apps will pick up on this and switch to vi-style keybindings.
I resonate with embracing the Zen of leaning into defaults.