I don't buy it. Bandwidth isn't much of an issue for desktop rendering. An old GMA950 does Vista fine in my experience, let alone today's CPUGPUs with much more bandwidth. All current IGPs even accelerate Flash and high bitrate HD video. Sandybridge even has a basic but useful super fast H.264 encode.
GPGPU isn't going anywhere for general computing, much to the chagrin of GPU companies who are trying to diversify when their low end graphics card market is vanishing before their eyes. There are a few niche areas that NVIDIA has some success in but that's it. Apps like bitcoin mining, folding and video encoding are inconsequential. Bitcoin mining in fact is leaving the realm of GPUs and heading into custom hardware from what I've read, because people with money are becoming interested.
IGPs are the future. Tablets, phones, PCs, game consoles, etc. Higher integration offers performance, power and cost benefits. Apparently in the future you can expect integrated DRAM designs too.