The thing is, not all strands of academia have collaboration even as a central focus. I don't see it very often in the humanities that articles or books have mu

The thing is, not all strands of academia have collaboration even as a central focus. I don't see it very often in the humanities that articles or books have multiple collaborators. The normal thing is either the article or monograph written by an individual. The other option are journals or collections made up of these kinds of articles. Sure, it's not unheard of that people collaborate, but even bigger projects usually follow the idea that what you publish is yours, so you are more likely to see a publication series with individual volumes by different people, or the above mentioned collections, where (maybe!) introductions or overviews are written collaboratively. This has partly to do with the dreadful "tooling" in many cases, i.e. in most cases Word with handwritten citations. If you are lucky, people use Endnote or Zotero. If you are really lucky, you might encounter somebody who knows what (Open|Libre) Office is. Your options for collaborations are thus: Google Docs (if people can manage the technical complexity) or mailing around Word files.