Comment by cmrdporcupine

GEM was very much an incomplete project, is my take on it. Which makes sense when you consider DR had to be -- seemingly for the life of the company -- pretty scrappy. Once Windows was on the scene, there was no point in them dumping a boatload of resources into it.

Its original advocate and designer, Lee Lorenzen, left DR to go create his own startup and make Ventura Publisher (which shipped with its own copy of GEM). Which was then bought up by Xerox. Which is also where Lorenzen came from in the first place before DR. (GEM came out of his desire to build out a Xerox Star-like system for commodity PCs, which he tried to pitch at Xerox but failed, so did at DR instead.)

On the ST side it went off in other directions, the two codebases forked significantly.