It always comes down to "it doesn't benefit them" eh…
There are some interesting situations though. Like in the big GPU world it's very common to document the ISA. Even nvidia does. I suppose that's because it benefits the vendor when games and GPGPU compute programs optimize for their GPUs, down to the assembly level. It's sad that Apple's approach is "just use Metal" rather than fully enabling developers to get to the actual… well, "metal"
There are some interesting situations though. Like in the big GPU world it's very common to document the ISA. Even nvidia does. I suppose that's because it benefits the vendor when games and GPGPU compute programs optimize for their GPUs, down to the assembly level. It's sad that Apple's approach is "just use Metal" rather than fully enabling developers to get to the actual… well, "metal"