As with many things at games studios using a different language (or unique technology) is usually driven by a single person. Once they leave or move out of the

As with many things at games studios using a different language (or unique technology) is usually driven by a single person. Once they leave or move out of the place where they could contribute and maintain it, unless it has support and buy in from the rest of the team and studio, it starts to gets replaced. From the grapevine I heard there was one person that advocated for writing in D, though I'm not sure if they are still there or not any more.