It's not perfect, as some people cannot resist using the C preprocessor for some bizarre constructions.
I used to write those bizarre things myself in C, and was proud of my work. But one day I decided to remove them all, and the code was better.
For C# Microsoft eventually embraced NuGet their package manager, and used it to put core packages that don't need to be fully available OOTB but can then benefit from frequent updates on a per project basis as opposed to updating the entire language runtime.
For Go it was the out of the box packages, like if I want to make a website, I can pull in net/http and their templating packages that come out of the box with Go, maybe a reasonably simple core maintainer package or packages that go into Dub would be a strong selling point. Right now Vibe.d is the only option for web dev, but there's no reason a much simpler web server couldn't exist.
For Rust, I just really love Cargo, I think its one of the nicest package managers I've ever used.
The other thing that would really help D is if something significant is built around D, whether it be a framework (like what Rails did for Ruby) or some major application that needs D to function at its core and is used by many, this could be a groundbreaking modern IDE, or anything really, a database that uses the best bits and pieces of D to scale, or even a really rich cross-platform GUI stack (my kingdom for std.gui to be a thing in D, and reasonably exhaustive).
I wish I had unlimited time and money, I would invest it in D. Alas, I'm not a language maintainer, just a guy who loves really good tools.
To the parent's point of startups, betting the farm on something like a particular language out of some sense of superiority might mean you are not focusing on the right problems. But if the founders happen to know a less widely used tool it doesn't seem inappropriate either. The type of employee that can drive a startup or a big tech project forward is not going to be thwarted by a language, and they might find something new to learn fun.
Maybe it exists and I am just ignorant but it doesn't seem to be in the list of supported languages.
Yes it isn't here today, just like it took several decades for optimizing compiler backends to do a very good job.
In fact one of the reasons why Matt Goldbolt created Compiler Explorer was to have a way to settle arguments he was having in the games industry.
... and the job of a programmer will be to explain, in as precise terms as possible, what they need the executable to do. (Reminds me of the idea of programming based on a natural language.)
We migrated from Asm to C. And C to C++, then to Java. And then Java to Python.
And now we write code in English.
I haven't written much code in many months.