However D still needs the ecosystem and support from platform vendors.

Unfortunately that was already lost, Java/Kotlin, Go, C# and Swift are the platform holder darlings for safe languages with GC, being improved for low level programming on each release, many with feature that you may argue that were in D first, and Rust for everything else.

Microsoft recently announced first class support for writing drivers in Rust, while I am certain that NVidia might be supportive of future Rust support on CUDA, after they get their new Python cu tiles support going across the ecosystem.

Two examples out of many others.

Language is great systems programming language, what is missing is the rest of the owl.