Optimal code line width has very little to do with monitor or window width. It's more of an anatomical restriction: the resolution of the human eye and the field of view.
For example, if we had 10 meter-wide monitors we won't be able to see them entirely from a close distance. Increasing the distance will require to increase the font, so the number of characters per line we can use doesn't change much.
Not so long ago I showed a piece of code on a mobile phone to a colleague, saying he should use shorter lines. He replied I need a larger display. When I opened the same code on my desktop display the lines were not fitting the editor window almost the same as on the mobile screen. (The angular sizes of a mobile phone screen and individual characters on it are approximately the same as of the bigger screen and characters on it because we keep phone closer to eyes).
I currently work with a codebase where long lines are used and it is so inconvenient. When I switch to some 80-cols code it is such a relief.
For example, if we had 10 meter-wide monitors we won't be able to see them entirely from a close distance. Increasing the distance will require to increase the font, so the number of characters per line we can use doesn't change much.
Not so long ago I showed a piece of code on a mobile phone to a colleague, saying he should use shorter lines. He replied I need a larger display. When I opened the same code on my desktop display the lines were not fitting the editor window almost the same as on the mobile screen. (The angular sizes of a mobile phone screen and individual characters on it are approximately the same as of the bigger screen and characters on it because we keep phone closer to eyes).
I currently work with a codebase where long lines are used and it is so inconvenient. When I switch to some 80-cols code it is such a relief.