Of course it can, but different killer apps for a different crowd. A missile tracking system wouldn't be the kind of application to do in PHP. Wrong app, wrong crowd.

I'm aware of D since it's inception more or less but don't know it very well. I would say D lacks a "bombastic" feature and maybe that's both the reason is not used more but also why is such a good language.

It's not "memory safe" like Rust, yes it's fast but so is C/C++, it doesn't have the "massive parallelism/ always-on" robustness like Erlang. It has a bit of everything which is good and bad.

Being a mid all-arounder is OK in my book, perhaps it's more a matter of some "post-AI" tech startup adopt it and get massive or famous, like Ruby because of the Web 2.0 era or Erlang with the Whatsapp thing.

Maybe D is good the way it is and will always be there.