Since we have version control, you can restart anywhere if you think it's a good place to fork from. I like greenfield development, but I suspect that there are going to be a lot more forks from now on, much like the game modding scene.
Companies with money-making businesses are gonna find themselves in an interesting spot when the "vibe juniors" are the vast majority of the people they can find to hire. New ways will be needed to reduce the risk.
...go to jail?