Yes, but nowadays this is just another bootstrap problem: editors don't support them because no documents use them, no documents use them because editors don't

Yes, but nowadays this is just another bootstrap problem: editors don't support them because no documents use them, no documents use them because editors don't support them, and users scream and bawl because their cheese has moved. Using an editor with some good support for control-character-separated data would be pleasant, more pleasant than the usual experience of fiddling with CSV in a text editor. That said, another nasty aspect of the bootstrap process would be running control-character-separated documents through standard text-processing tools and pipelines and finding out how many of them strip non-tab control characters, turn them to spaces or mangle them pseudo-randomly. I think the more fundamental problem with using the ASCII control characters is that there's no way (or rather, no obvious and standard way AFAICS) to use them to define (most) recursive data structures. That's not a problem when you stick to simple CSV-like arrays-of-arrays, but it's enough of a restriction to make one wonder if bringing ASCII back is worth the battles.