I don't think there's any reason for textboards to be so unpopular here in the west at this point. Today's 4chan (well, 4chan minus /b/ and the hentai boards) is filled with discussion. People actively discourage image dumps and macros and spend most of their time discussing rather than posting images. I think if moot had used Kareha on every board but /b/, things would be exactly the same, minus the "pic unrelated" footer on every parent post.