Like with C in systems programming, the targeted users must be willing to try new ways, and most aren't.

Here is your GPU mention,

"Targeting GPUs and Other Hierarchical Architectures in Chapel"

https://chapel-lang.org/presentations/SC11/05-sidelnik-gpu.p...

"GPUIterator: bridging the gap between Chapel and GPU platforms"

https://dl.acm.org/doi/10.1145/3329722.3330142