alt Hacker NewsIt's true that there is no off the shelf tool that you can use right now to write your app, but it certainly doesn't prove that making such a tool is impossible or even complicated.
It makes sense for a complex productivity app (e.g. an office suite editor) to implement the UI from scratch anyway, and for that they may choose D. If Jane Street didn't pick OCaml, it would've died long ago -- in the same manner, some company might pick D to do UI or anything else really.
It is extremely complicated to do so yourself.
Handling energy efficiency/a11y/i8n is non trivial in any language, using the paved road of the system's native implementation solves for many of those problems out of the box.
You would need to reimplement all of that in D lang for your UI layer, and all you wanted to do was build an application to solve a problem, you weren't in the business of building a UI library to begin with.