In practice (I.e. actual practice that pays my rent) it's been good enough for me

Then why did D get lapped by Rust if @nogc is good enough and the ecosystem is good enough?

If the answer is along the lines of "corporate backing", why did Rust get corporate backing and D didn't?

Rust did memory safety better than D did, which was a very attractive prospect and then Rust was also lucky enough to get a following of people who very noisy about it.

Also in a world where JavaScript (excel, even) is dominant let's not ascribe these things to purely rational factors.