Just another 5 cents...
If say, todays 6 gpu rigs push out 250-350MHs, then with VEGA's this limit is higher and already climbs to 400MHs if not more, then comes March of 2018 and NVIDIA rolls out their 20xx GPU with capability of pushing 100MHs from one PGU, having 6 GPU rig pushing 600MHs is dam close to rumorish 650MHs, the only difference would be power this rig consumes vs the power this ASIC will consume...  IT WILL ALL COME TO _ROI_ at the end.

P.S. usage of DDR3 or GDD3 still leaves me wonder...