Given that Anarki exists and appears to be updated reasonably frequently, it seems likely that, unless pg does something, sheer genetic drift will cause Anarki and ArcN to diverge enough to become separate and incompatible dialects. If someone makes a killer app in Arc, and uses Anarki-specific extensions, it may very well be that merging ArcN into Anarki may be too difficult and possibly even counterproductive (e.g. if too many names in an Arc3 conflict with names on Arc2-based Anarki).
If it goes on for longer, both may even evolve into entirely different languages (like Scheme and CL). Might make a good study of memetics and the origin of programming languages ^^.
