The problem is that C and C++ do not implicitly parallelize well. To get maximum bang for the bunk you want to extract lots of parallelism. Which requires a different kind of language.

The interesting flip side is that if you design for easy parallelism, you are better able to take advantage of multiple cores in standard CPUs. Also you can then turn it around and also distribute the same program across a cluster of commodity hardware on the cloud.

But yes, the toolchain matters. A lot.