Can't it be both? or none of the above? I don't know anything about D specifically, but effort spent here is likely to be valuable elsewhere. Either because of

Can't it be both? or none of the above? I don't know anything about D specifically, but effort spent here is likely to be valuable elsewhere. Either because of techniques learned, or approaches validated. Even if D never catches on, folks will learn from what they've done. And the folks who did it, will likely be able to get jobs in the field. I doubt the effort is truly wasted.