"Good tooling, good libraries, proven track record" are all relative concepts, it's not something you have or don't have.

There are serious projects being written in D as we speak, I'm sure, and the language has a track record of having been consistently maintained and improved since 2001, and has some very good libraries and tooling (very nice standard library, three independent and supported compiler implementations!) It does not have good libraries and tooling for all things; certainly integrations with other libs and systems often lag behind more popular languages, but no programming language is suitable for everything.

What I'm saying is there's a big world out there, not all programmers are burdened with having to care about CV-maxxing, community or the preferences of other devs, some of them can just do things in the language they prefer. And therefore, not everything benefits from being written in Rust or whatever the top #1 Most Popular! Trending! Best Choice for System Programming 2026! programming language of the week happens to be.