" We have no doubt that the Bokeh filter and the GPU Water Simulation options could have been executed successfully on AMD’s Radeon HD 5000 series of GPUs. That the developers chose NVIDIA’s CUDA technology over Microsoft DirectCompute or even OpenCL is probably due to the fact that NVIDIA’s developer relations team worked with Avalanche Studios developers, and of course they like to promote their own products. (We would surely love to see the contract between the two, but that will never happen.) It is certainly their right to do so, just as it is Avalanche’s right to choose whatever API they want to use. We would certainly not presume to tell any independent game developer how to design their own game, but we would suggest that a more open alternative (such as OpenCL or DirectCompute) would have been preferred by us for those gamers without CUDA compatible hardware.
This is an old argument, and is basically analogous to the adoption of PhysX as opposed to a more broadly compatible physics library. NVIDIA wants to increase its side of the GPU business by giving its customers a "tangible" advantage in as many games as possible, while gamers without NVIDIA hardware would prefer that game developers had not forget about them."
http://www.hardocp.com/article/2010/05/04/just_cause_2_gameplay_performance_image_quality/7
It's not as if it wasn't mentioned for years that if AMD pursued similar game promotional methods that we'd start seeing what has started to occur, game performance being more brand oriented.