Lemme educate you, son.
The 80 column limit is by no means arbitrary, or a mistake. Back before you were born, in the dark ages before RGB, terminals had 80 columns, thus coding style locked into that column width. For a long time, word wrap wasn't even a thing. (some coding languages and shells to this day use a backslash to denote a continued line, that's why.)
Eighty columns is legacy, maybe even tradition, for sure, but not at all arbitrary. (I don't have space/time/desire to explain 'why 80', but the info is out there if you seek it.)
If you're still programming in a terminal then you're a weirdo, but the limit is no more arbitrary than other standards, current or outmoded, like 24 fps standard for filmed motion pictures, 4:3 ratio of broadcast TV, or the number of scanlines on a 4k display. All of this stuff is at the intersection of technological limitations, standardization and budget at the time these things were originally being worked out.