I love D and one space I want to see more of is DMD on SBC's and moreso than that D running on WebAssembly, Go and Rust do it. I consider Rust and Go the main competitors to D, not sure if others would agree, but that's just my view. Other than that it's a great language.
Let's be real, in the real world D, go or rust are not competitors to anything. Just take a look at http://www.modulecounts.com to see the gap between language ecosystems.
https://dlang.org/orgs-using-d.html
https://www.rust-lang.org/production/users
and we know plenty are using Go in prod, including Slack, Google (heavily for YouTube's database layer), and many others.