I think the nomenclature gets muddy here, at least for me.
I've heard people talk about 4k, ultrawide, and 4k ultrawide... and I don't know how you get 4k ultrawide
To me :
4k = 4096 x 2160
ultrawide 3440 x 1440
4k ultrawide = ?
So for the purpose of this discussion I'm going to assume the first two resolutions..
I'd assume 4k would dominate gaming, even moving forward. With 4K blueray and consoles and television manufacturers going that route now, why would devs deviate? More and more gaming PCs are being played on the living room television (thanks vr), I don't imagine computer games rushing off to a different resolution.
ultrawide has a great advantage in business computing. More screen realestate for multiple apps up and less demand on graphics card, not to mention no pesky beezle when computer to a multiple monitor scenerio. I use two monitors at work and three monitors at home and it limits me to how i can size the applications i have open. I can't span something inbetween two monitors.