Why are you working so hard to avoid source control? It solves the following:
- assuming you use github, gitlab or chiselapp (fossil hosting), it provides a practically free way to keep multiple machines in sync. You could also just use something like dropbox or an S3 bucket.
- if I wanted wanted to see commit history (what you're calling logs) in the file I'm working on, I'd create a src block that ran a command against the source control system and formatted the results appropriately. While I haven't done this with commit messages, I have done it on export to record the exported version.
I avoid git (work) or fossil (home) with literate org files as I don't want a full repository for a single file so I'll use rcs or sccs with emacs vc-mode.