Even if multi-screen are becoming "more and more common", High end performance PC are not that common, and among them, multi-screen are also not common. So I'm not sure about the fact that the percentage of multi-screen "gamers" is really growing.
Those specific setups remain a (small) minority of the overall PC players (and it's worse if you considere TV-consoles).
You of course still can ask for such a support, and this is totally legit by itself !
(and I'm thinking they are already working on it)
You don't need to involve some random stats, because I'm wondering if the implied "democratization" is real.
PS : and even later in years 2020 and later, a lot of games will still not implement ultra-wide support for the simple fact that it adds nothing to them, and in some ways for a bunch of genre, it literaly force to change the gameplay, balance, and in multiplayer, it makes the game just unfair between players. (that making games even more social-class-ranked, over the already problematic CPU-GPU and netcodes performance issue)
A high end pc is not requirement for Ultra Wide monitors. The average UW monitors have their resolution between 1440p and 1080p. BTW as a guy said before me the uw and the multi-screen are not the same thing. For multi-screen you have to buy more then on monitors. While the ultra wide is just one monitor. A bigger one. In the classic cinematic scale: 21:9. This monitor should be more common since ages because the 21:9 is older then the 16:9. AND it's not popular because people don't know how good it is. If you can run games at 4k, you will buy 4k monitor, right,? BUT you can buy 3440×1440 instead. The +screen really worth it. It looks so much better, and gives adventage in competetive games of course, but a better mouse, a better pc, or a monitor with 120Hz gives you advantage too. Then what are we talking about? It's like complaining about why the big teams e.g. in Forma 1 better then the smaller ones. They have more money. That's all. I think everybody should try it out and buy one if he/she can buy it because it's really good. :D The only bad thing about it the less support compared to the 16:9. (like in tha case of this game.) But you can play this game too without scratched sceen. So it's okay.