Most engines are moving toward some form of GI which is multitudes more expensive than traditional lighting and then we multiply that with some volumetric lighting and voila, 4K isn't even moving the richter scale anymore and 1440p is playable where it was smooth.
That's a very short-term outlook. GPUs will continue improving in performance by 50-70% every 2-2.5 years. Last year we got 980Ti/Fury X. For simplicity's sake, let's assume Big Pascal beats 980Ti by 70% at 4K June 2017, then Big Volta beats Big Pascal by 70% at 4K June 2019. That means by September 2020, $350 next gen card should be 1.7x1.7 = 3.4X faster than 980Ti.
Even though the overall GPU volume unit sales are declining or at best stagnant, the $350+ GPU market segment is growing.
These gamers who are buying 2015-2016 $350+ GPUs are likely going to be looking to get a 1440p-4K monitor, and later FreeSync/GSync, 120-144Hz 1440p, HDR, etc. Why? Because, the types of gamers who are still interested in desktop PC gaming are spending $$$. They want cutting edge tech. It's why Intel is posting record i7 and record K series CPU sales quarter after quarter. Think about it -- more i7s sold per quarter in the last 2-3 quarters in Intel's history than even during the i7 920-930, i7 860, i7 2600K, i7 3770K generations and we know how insanely popular those CPUs were.
Even on this forum, many people have ditched 1920x1080 in favour of 2560x1440, 2560x1600, 3440x1440, 2560x1080, 4K, etc.
Think about this, by February 2015, Steam already had 125M users.
https://www.vg247.com/2015/02/24/steam-has-over-125-million-active-users-8-9m-concurrent-peak/
It wouldn't be unrealistic to extrapolate that by April 2016, there are already 140M Steam users, if not more.
If 7.5M gamers had 970/290X or above by February 2016, let's assume that base grew to 8M by now. Let's assume 90% of these gamers use Steam => 90% * 8M = 7.2M.
7.2M / 140M Steam userbase = 5.1%
Now let's look at gamers with above 1920x1200 = 2.171%
http://store.steampowered.com/hwsurvey
That means potentially a large number of PC gamers with R9 290X/970 and above are gaming above 1920x1080 already. Of course not all of them are using monitor above 1920x1200 but the point I am trying to make is the average Steam PC with a 1920x1200 and below monitor should not be compared to the average gaming system with an R9 290X/970. Therefore, when we start discussing Fury X/980Ti level of GPU power and 1080p gaming benchmarks, it's not the proper context of how I would imagine a lot of R9 290X/970 and above gamers are gaming.
Getting revved up for 4K was a waste, 1440p not so much but it's not as if games are going to stop evolving especially with the nextgen's just released. Though Vega and Volta may be able to clean up 1440p for some time, developers may start to use cleaner real time lighting methods and then your back in the hole again.
So you are saying June 2015-June 2016, Fury X and 980Ti were great 1440p cards but the minute Polaris 10 comes out, suddenly they are 1080p cards, that day?
I think your going to find 1080p being the goal post resolution for the foreseeable future - it's best to just write 4K off fttb.
If 980Ti becomes only good for 1080P in 2016, that will be mostly the result of horrendously optimized console to PC ports like Hitman/Gears of War or if we get a wave of true next generation titles that blow us away graphically (aka the next Crysis 1/3, Metro 2033). Alternatively, a barrage of Unreal Engine 4 games that run like crap on almost everything (ARK Survival Evolved).
As of February 2016, AMD estimated that there were only 7.5M PC gamers with GTX970/290X and above.
I would be surprised if it even reached 10M by now. If Fury X/980Ti level of GPU horsepower becomes the norm for 1080p gaming in 2016, then it spells doom for the PC gaming industry, unless you think the remaining 120M+ steam users are all going to be upgrading?
What's going to happen with new gen cards is Fury X/390X/980/980Ti levels of performance will become more affordable. That doesn't mean the minute that happens in June 2016 that Fury X/980Ti are now 1080p level cards.