Afaik, nvi actually doesn't have all the features of the original vi. According to Wikipedia, "The aspects of nvi that are still marked preliminary or unimpleme

Afaik, nvi actually doesn't have all the features of the original vi. According to Wikipedia, "The aspects of nvi that are still marked preliminary or unimplemented are, for the time being, likely to remain that way." Moreover, nvi had been developed for a little while after the various BSDs stopped syncing with upstream due to licensing issues after version 1.79. I honestly think the reason no one develops it anymore is because no one cares. It's good enough for use in emergencies, and beyond that, it's either good enough for the people who use it, or they just use a more featureful editor.