Yes, but it is not installed as the default text editor. Unlike vi/vim/nano

The default is usually vi or nano, not full vim. So installing vim or neovim should take about the same effort.

In what distros? Ubuntu comes with vim.

Yeah, but it's vim.tiny. They don't even alias it to `vim` because it's not full vim.

Debian Stable (without a DE) only comes with nano AFAIK.

It has vi in the base system, specifically `vim-tiny`. Vi is mandated by POSIX, so pretty much every distro includes some minimal version of it in the base system. `nvi` is also used sometimes instead.

I'd bet good money both ed and vi are there as they are specified by POSIX iirc.