The probability of folks being able to get mining chips made on a 7nm process next year is pretty much ZERO.
2019 - perhaps, but even THAT is looking very iffy.
For perspective - Intel MIGHT be shipping 10nm late THIS year, and they've been working on THAT node a lot longer than anyone has been working on 7nm (and Intel is USUALLY the first folks to market with usable chips on a given node).
Keep in mind some history - 14/16nm was first ANNOUNCED as being available almost 2 YEARS before the first actual products hit retail using THAT node.
10nm has proven to be MUCH more difficult, and preliminary indications are that 7nm (in the cases that will actually BE 7nm) is going to be much much tougher yet.
Mining gear hasn't so much "stagnated" as it finally caught up to current state-of-the-art on semiconductor technology, so it doesn't have the OPTION of "move to a better node every year or less" any more, it has to wait on the INDUSTRY to be able to move - which has commonly been a 4-6 year cycle and seems likely to get WORSE as semi tech has gotten well into the range where quantum effects and the limits of silicon are bringing Moore's Law to it's knees.
Intel has said flat out that "10nm is the end of the road for silicon", IBM has already announced that it's work on the 7nm node is using HYBRID Si/Ge wafers because pure silicon couldn't scale any more (but Germanium isn't going to be able to scale much further than Silicon)....
I'm not going to be shocked if 7nm is the END of "standard" semiconductor technology, at best I'd guessing the next node after THAT will be 10 years more-or-less down the road.
It might be time for alternative tech to start getting itself OUT of the lab, like carbon nanotube electronics....
Umm Apple's 10nm A11 chip is already in full production and will be shipping in their iPhone 8/X in a few weeks...they are already working on 5 and 3nm chips as well, so 10nm definitely is not the limit.