I wouldn't say desktop discrete GPUs are dying per say. The demand for them just depends very heavily on major PC games coming out and upgrade cycles. With software far behind hardware, many people are taking far longer to upgrade their desktop/laptop. If the next popular game like WoW, LoL, Starcraft 3 or BF5 come out and they make 750Ti feel slow, there will be millions of upgraders. We cannot expect desktop dGPU sales to continue growing quarter after quarter when there is a serious drought of next generation PC games at the moment. We are just entering the current generation of consoles and it will take some time for developers to move on from PS360 outdated game engines and targeting that userbase.
It's just a foregone conclusion that Intel will continue to grow GPU market share because every fall when kids go back to school, there is bound to be a desktop or a laptop sale but not everyone of those will need a dGPU for games. I can't remember a time when I haven't upgraded the GPU in nearly 3 years but it's closing in very quickly. Obviously there are going to be less and less people upgrading to GPUs every generation as in the past if the increases in GPU performance are no longer 0.75-2x but are more like 30-40% and there are very few upcoming demanding PC games.
The greatest consequence is likely higher mid-range and high end desktop dGPU prices. We first saw more or less an elimination of the <$100 dGPU space on the desktop and I think soon the $150 space will start getting encroached once AMD/Intel move on to some form of stackable memory to drive APU bandwidth. GM200/210 at $700-800 and GK104 at $450-500 is probably going to be the new normal whereas in the past these were $250-350 and $500-650 GPUs.