It does appear that the sub-USD800 and sub-USD1000 and closed back markets are the new focus and definitely ready, primed, and in need of/for a major shake up. Definitely can say that closed-back tech needs to catch-up to open-back.
It will not be surprising if some top-tier performance audiophile closed-back headphones soon appear out of this awakened market segments (sub-USD800 & USD1000) with a high probability that they could even be as low as USD350-500 where many place the diminishing returns demarcation. The HD6xx have proven that it can be done and after their seemingly never-ending success it would not make any sense for companies to not go after this segment again... albeit via lower impedance closed-back models (due to mobile devices) and at even more competitive pricing (sub-USD500).
I was reading somewhere that it is predicated that a new budget king of audiophile tier-one grade headphones will appear this coming year with sub-20 ohms impedance and a sensitivity/efficiency well below 100 dB/mW (possibly nearing 95 db/mW as mobile devices are predicted to get even more powerful due to recent battery and op-amp efficiency technologies). The Aeons appear to be proving this prediction correct (14 Ohms; 97dB/mW) and will probably spark/kick-start a race at this market segment which was kinda started by the Sines with their 20 ohm impedance and >120db SPL/mW specs and target customer market.
The soon arriving HeadRoom Cosmic along with the Senn HD820 might indeed be these new kings and if under 1K or less, budget as well...