[hobs]

I came to say this exactly. In a commercial project where time and money are limiting factors, you are almost insane to rewrite from scratch.

In an OSS context, money is not always the biggest mover, and doing this might actually succeed, or at least not fail because the company fails. It certainly may be that the people lose interest before it gets anywhere, but who cares! The only reason that I could see is that someone wants to fold all their code changes back into vim's original codebase, and they both seem to have different end goals, so eventually they will drift away from each other.

Code evolution.