You sure about that? With ProgPoW having to make FPGA's replicate a GPU, it will erase benefits of specialization, and as such will make a GPU more cost-efficient as they have economies of scale at their side.
First we need to see progpow in action, i.e. adopted by coins. My guess is that we will continue to have different kinds of POW - ASIC-, FPGA-, or GPU-friendly - and the debate will take years to settle, if at all. There are still CPU/HDD algos out there refusing to die.