Im not entirely convinced that lack of use throughout art history proves its
Ineffectiveness in modern computing. For one, a painting is more like a television than a computer monitor, it would be positioned at a reasonable distance. For a second, this kind of art is completely static so having comfort in peripheral viewing is less important. If a painting is hugely wide, its not necissarly important to see it in one glance, you can move your head.
Also, there any many things that were discovered or invented in recent generations that you would have thought existed a long time ago. Maybe they just didn't think of trying it?
Indeed, especially when a monitor is as wide as those ones are. I can see both edges of my screen but with a 34", that might push it a bit too far for the distance I am from the screen.
Think of ultrawide screens like normal aspect screens with a chunk chopped off. 29 is like a 32 and 34 is like a 42. Put those size screens in front of your face and it would be uncomfortable as hell.