Manufacturers are heading where the money is at, which, to be honest, isn't a bad choice, I mean, more money = better products (, usually).
With Zotac having put a 1080 Ti in a smaller package, ASRock putting X99 and X299 in ITX format, Gigabyte putting a 1080 in 170mm lenght, I'm sure we they can achieve this for the 20 series.
Bling'd PCs are the rave now, not our niche SFF, but a manufacturer should cater to all venues as they've had in the past to not lose that market share as we do not know they evolution in 2-5-10 years.
Cooling getting more and more efficient is what enables GPU and CPU manufacturers to increase heat output in exchange for higher performance, the highest end monitors we're using in 2018 (4k/144hz) are basically impossible to peg with single GPU solutions and even harder for SLI configurations (not saying Crossfire because they're not there yet). Monitor advancement is going too fast for Nvidia, which to be honest, is prolonging as much as possible to give as much chance to AMD as possible. (we can see this by looking at the time between releases for Nvidia).
NVidia probably has next time almost done, but we might only see it in 2-3 years.