On the other hand, the amount of software using a language and the decision to use a language is mutually reinforcing, and both are only loosely correlated with

On the other hand, the amount of software using a language and the decision to use a language is mutually reinforcing, and both are only loosely correlated with the quality of the language. Ten years ago, there were almost no successful projects using Lua, but now there are many, and the language has barely changed at all -- likewise for Erlang. D is newer than either of these and occupies a niche in which other languages are deeply entrenched. I'd give it more time before writing it off.