Or is the usage of Spacemacs primarily attributable to it coming earlier to the scene?
Yeah, pretty much just that. If was to start again now I’d consider other options, but I have no serious complaints about spacemacs. I probably would have never got into Emacs at all if I had to start with vanilla.
Furthermore, as you’re using it in “VI mode”, would it be fair to assume that you’ve got some experience/history with Neo(Vim) as well? If so, what led you to making the switch from (Neo)Vim to Emacs?
Yeah, I used VIM (and I still do when I’m in an unfamiliar environment), but only before neovim existed. IMO Lisp is what makes Emacs great, and vimscript is (was?) an absolute nightmare for anything complex. I don’t think lua is a bad language, but I’ll still take Lisp any day for this purpose.
I’ve also got my concerns related to what degree the containers can be sandboxed. Do you happen to have some insights on this?
What I described isn’t using containers. Nix just provides an environment for processes to run in, and direnv-mode ensures it’s using the right environment for a given buffer in Emacs. So for example I don’t have OmniSharp or dotnet in my user $PATH, but they are provided by the nix expression in a particular project directory. That allows lsp-mode to start OmniSharp as a language server, or I can run dotnet build using the Emacs compile command.
You can define containers with nix and manage them with nixos-container. I do that for testing server deployments, or running sandboxed services, but I’ve never needed something that complex for a dev shell.