Every Unix machine (Mac or Linux) that I've ever tried to use nano on has had it preinstalled. I'm sure not all of them have it preinstalled, but it's common at least in mainstream distros
More recently, I've found myself inside a container which didn't have any editors. I got the job done with echo, head and tail. Delightful.
Even alpine based images have a version of vi (it comes with busybox)
I agree this is pretty much a non issue for the average developer, but those of us who work on network infrastructure, as red-team hackers, or do any work on embedded systems can attest to how much of a pain it would be to not know how to use vi/vim.
You haven’t lived till you have to edit using only sed.
But not having a basic text editor that is probably a few hundred KB feels a bit silly, especially given how many environment dependencies usually get packaged into containers anyways.
That's like not including any sort of a shell in your container and wondering why people are having troubles with debugging.
Personally, i think that just basing container images on something like Alpine, Debian or even Ubuntu images is good enough because those are stripped down enough already for the most part.
# pkg install nano