Any user who deals with a set of files that need to be coherent, such as a source tree, I'd argue is already most likely technical. Non-technical users are used to having the time dimension, but for individual documents. They understand the notion of revision A and revision B of a document. Most people also most likely understand that if two people edit revision A, they would create separate, conflicting revisions B.

but: most people also accept wihtout fuss, that it's OK that you make a phone call or email and just agree who throws their version out. Or that one user should simply lock the document for editing to prevent this from happening.

"Git for non technical users" (of single documents, not trees) seems pretty easy to build as a layer on top of git. 1) you use LFS and file locking. 2) You "check out" a file for editing which locks it exclusively 3) You completely hide the notion of "local repository" because zero nontechnical users, ever want to be bothered with distributed version control. Basically - you make a dumber but more robust verison of SVN on top of git-lfs.