You miss the point that GPGPU will become mainstream very soon. For example, Apple won't just release OpenCL – they will be sure to use it too. Video encoding, image processing, game physics, sound procesing – there are lots of possibilities for a normal user. Cuda is already used by never Nvidia drivers to provide PhysiX acceleration.
But I agree that it is pointess to base GL on GPGPU – it is a distinct API. This two things must exist in parallel.