A useful question is ‘how much better?’ For so many reasons, SVN to Git was a no-brainer but still constituted significant migration costs for existing teams a

A useful question is ‘how much better?’ For so many reasons, SVN to Git was a no-brainer but still constituted significant migration costs for existing teams and codebases: training, retooling, high-fidelity data transfer (you retained the commit history, right?). For a tool with such wide adoption, motivating an ecosystem to move where there are many actors with different incentive structures, some of them will look and say ‘30% better isn’t even close to sufficient to spend time and $$$ on this. I would need ~10x better and/or a gain of altogether new capabilities impossible in previous tool to motivate that.’ It’s great that jj can be used independently without needing the whole ecosystem to move today, but once/if that part changes I’d expect it to be a long slog towards re-standardization if ever. But jj likely already fully anticipated this given its compatibility with the Git wire protocol in the first place and I doubt it would ever give that up given the current landscape.