WordPerfect died for two reasons: the transition to Windows (and WP6 for DOS, which was the worst of both worlds); and its lack of a real office suite integration. Lotus 1-2-3, the other application that owned to office, lost out for much the same reason. SmartSuite was a whole lot closer to an integrated solution than bundling WP with Quattro Pro and friends was, but Ami Pro was a less-than-competent word processor for business purposes.

TeX/LaTeX may make some pretty documents, but the learning curve is pretty heavy-duty, and compiling a typeset document isn't exactly dash-it-off quick for normal typist/secretary activities. It doesn't matter much what you can do with technical or book-length documents; that's not what the world runs on.

And Gimp ain't Photoshop. It's not even a close thing.