Saving drafts on the other hand could help avoid many conflicts on less-trafficked pages. 

Right now, on a page that is edited infrequently, this happens: 

- User A starts an edit

- User A saves not to lose work, not quite done yet.  Resumes the edit. 

- User B (typically an editor) sees the edit by A, and sets to work polishing it.  Saves. 

- User A saves --> conflict

The first edit by A "woke up" B, and led to the conflict. 

If we allowed saving drafts, the following would be more likely: 

- User A starts an edit

- User A saves a draft, and continues the edit.

- User A saves the edit. 

- User B (typically an editor) sees the edit by A, and sets to work polishing it.  Saves. 

The conflict would occur only if A had second-thoughts about the edit and continues work after saving it, which might happen, but les frequently. 

Of course saving drafts is also cumbersome to implement at scale (how long would they persist?  there would be clean up needed, etc; maybe they could persist for one week then be mailed back to the author and deleted?).