I don't know if it will be D, but I am 100% sure they will change.

First there was only Assembly, C and Pascal dialects were dog slow, and the OS vendors forced them to go C.

Then there was only C, C++ was dog slow, and the OS vendors forced them to go C++.

Then there was only C++, language X was dog slow, and the OS vendors force them to go language X.

The question is what language X stands for.