Good question! Idk and I don't make the rules. I guess people default to it because most people have git installed already?

I'm thinking of LazyVim for example which has [1]:

    git clone https://github.com/LazyVim/starter ~/.config/nvim

After that, once you do a sync or update, there's a whole lot more cloning going on.

The other projects I was going to mention have apparently all switched away from using git for their package management (homebrew, Go, cargo, ...). I can't help but wonder to what extent that might have been influenced by the default slowness of doing a full git clone?

Of course these all could add `--depth 1` to their instructions or internal package management tooling, and ofc we need both options to be available. I pondering aloud that in my observation, `--depth 1` is probably the option that I want more often than not but YMMV.

1: https://github.com/aerys/gpm