First: Can your GPU handle that at better than low quality 20 fps? If you have a gpu that can handle 4K fine, then it “should” be able to do 3x 1080p monitors (because there are 4x as many pixels in 2160p than 1080p). Playstation and Xbox are pretty much right out of question (no custom controller support likely anyway), and 3x 1440p or 3x 4K is most likely out if you don’t have a top end GPU. Having a wider field of vision may need beefier CPU power to calculate bullet physics and other things in view as well.
Second: How many Armored Core players would have the money and need to buy a custom controller, a highend GPU and 3 monitors (assuming 1080p), back of the napkin math says 2200 CAD = 1620 USD? While support for crazy setups are nice but the developers aren’t really in a rush to add support for stuff that at most a few hundred people worldwide will make use of. Racing sim and other simulator fans have the audience there, I don’t know if ACVI is billing itself as less arcadey and more simulation.
However, if mod support is there, perhaps interested fanatics would add multimonitor, custom controller and HUD support.