This "hurr durr, we aren't on terminals anymore" argument is dumb. You aren't arguing with crotchety old geezers or people with stupid hardware choices. Quit assuming the people who disagree with you are idiots.
With the project side panel open enough to see most of the project's directories it uses ~370px. The minimap (which I do leave open, and use, often) takes up ~50 pixels and the scroll bar for the edit window a final ~20 leaving me with 840 pixels that can show just at 100 columns. If I kill the minimap I get almost exactly 120 cols.
For me, I have no qualms about 79 cols for the limit and enjoy being able to use my windows split to half the screen and still have some breathing room around the right edge of my code. I also find it awkward to scroll horizontally to see what's going on in a long line.