Do you really only look at one file at once? My laptop's display is ~1600 pixels wide; that's enough for 3 terminals, all viewing different files, if I keep them at 80 columns wide. If my terminals are wider, I can only see two files at once. When I'm using multiple displays, I'll generally have consoles in one display and a browser in the other, or six consoles (my brain is small, so I need lots of files open to keep track of how things work). 80 columns is just a nice width for reading things; it's about what a book uses, and it's what most people are used to. Why not stick with it?