Aren't modern word processor formats just zipped-up XML files? I suspect it should be a straight-forward matter to get at least LibreOffice and version control cooperating.
You are technically correct, but not usefully so. The XML is pretty hairy. A VCS that handles XML semantically (e.g. tag-pair oriented, rather than line-oriented) might have some shot....but, basically, merges are more or less not going to work so it's not really version control, just backups.
