How will these languages emit machine code for every variant of GPU/CPU/DSP/Vector/FPGA/whatever architecture they might run on? This isn't as simple as it sounds.
The host binary will include intermediate representation of the compute code to be compiled by the device driver.
This already exists, see SYCL + SPIR-V. Intel's oneAPI is one implementation of this approach.
no, these are really big and interesting back ends. still, socially, that has to be better than _everyone_ breaking out the datasheets...if they even have those anymore