Right now, it would appear that Bitmain doesn't expect this to happen. They are apparently "all in" on the SHA256 ASIC road (for good or for bad). I share that opinion as well.
They also appear to be beating competition at releasing 16nm that meets spec, looking at sales page -
https://bitmaintech.com/productDetail.htm?pid=0002016052907243375530DcJIoK0654 . So that is huge on getting that big of a efficiency jump.
Will be intersting to see Bitfury and BW's response to how quick they can get gear out of next gen. Some chips of BW were shown in mining forum but I don't think we know if efficiency was met on those.
One thing is for sure that it will be interesting times going into having, and after.