[pjmlp]

The problem was never the GC per se, see TinyGo, Astrobe, microEJ, Meadows among others, rather always chasing the next big thing that could bring users, while leaving the other behind not fully done.

Now C++, Java and C# have many capabilities where D had an upper had back when Andrei's book came out, and naturally new competition also came into play with better corporate support.