part of the reason is historical cruft & history path dependency. GPUs didn't start as general computing device for parallelism but a device for the specific purpose of accelerating graphics with very specific fixed functions for that job and only that. with time that fixed pipeline became more complex and more configurable, not fixed/more flexible and hacks were in parallel used to make use of it for tasks outside graphics those hacks were later made into something more formal (CUDA/OpenCL).

CUDA being the winner (closed source, not really usable on non-nvidia GPUs) between those 2 and nvidia not wanting to open their competitive advantage to the competition for the niche of non gamings uses / scientific computing (and later AI, which became a huge win for nvidia).

vulkan came around after as this open thing (based on a previous attempt by AMD called mantle) that's trying to break down the leaky abstractions and the divide between language for graphics & video games and separate language/frameworks for gpu non-graphic computing with the promise of giving more control and more room for squeezing performance from the hardware at the cost of more complexity with the idea that you'll probably build your own abstractions on top of it for your subset of applications.

If GPU were from the get go designed as a parallelism tool first and video game tools second the hardware architecture and the language would probably be different than today and simpler (and if the competition between the duopoly didn't sabotage things)

don't forget that the drivers for GPUs would until recently get updates to patch specific video games for performance issues (not sure if they still do that ?)

Good summary, thanks. Sounds like it's all still pretty early, even for graphics but much more for parallel compute, which seems the direction the hardware is going in. I'm sure there is a CUDA equivalent for CPU but I would guess it's all the way back in the 70s or earlier. Hopefully open standards gets some traction.

> If GPU were from the get go designed as a parallelism tool first and video game tools second the hardware architecture and the language would probably be different than today and simpler (...)

The market demand was for video game tools, though.

People didn't wanted faster compute, they wanted their computer games to work smoothly on the hardware they already own. Therefore, they preferred to spend 100-200€ on a point upgrade, much like RAM, than scrapping their 2k€ PC.

To give people a reason to buy these upgrades, games had to use them. Therefore video cards were designed specially for the usecases and development flow that game developers already followed.

If it wasn't for the video game market, NVidia wouldn't exist as we know it today.