Also D is older than Go and Rust and only a few months younger than C#. So the question then becomes “why weren’t people using D when your recommended alternatives weren’t an option?” Or “why use the alternatives (when they were new) when D already exists?”
This is only true in the most technical sense: you can easily opt-out of the GC, but you will struggle with the standard library, and probably most third-party libraries too. It's the baseline assumption after all, hence why it's opt-out, not opt-in. There was a DConf talk about the future of Phobos which indicated increased support for @nogc, but this is a ways away, and even then. If you're opting-out of the GC, you are giving up a lot. And honestly, if you really don't want the GC, you may be better off with Zig.
But popularity/awareness/ecosystem matter.
Especially with Nim it's so easy to make quality libraries with a Codex/ClaudeCode and a couple hours as a hobby.
Especially when they run fast. I just made Metal bindings and got 120 FPS demos with SDF bitmaps running yesterday while eating Saturday brunch.
A standup comedian from Australia should not assume that the audience in the Himalayas is laughing because the LLM the comedian used 20 minutes before was really good at translating the comedian's routine.
But I suppose it is normal for developers to assume that a compiler translated their Haskell into x86_64 instructions perfectly, then turned around and did the same for three different flavors of Arm instructions. So why shouldn't an LLM turn piles of oral descriptions into perfectly architected Nim?
For some reason I don't feel the same urgency to double-check the details of the Arm instructions as I feel about inspecting the Nim or Haskell or whatever the LLM generated.
You have to push for them to add tests. It also helps if you can have the LLM just translate from C++ to Nim.
We’re certainly not at the age of LLMs generating code on the fly each time.
Thus, it makes very little sense to adopt D versus other managed compiled languages.
The language and community are cool, sadly that is not enough.