My unpopular opinion is that computing is stuck in a local maximum based on technology from the 1970s. In particular, typing into an 80x25 terminal window with unformatted fixed-width characters should be obsolete; we don't need compatibility with punch cards any more. There was a thread a week ago about displaying graphs in your terminal using ASCII graphics. This shouldn't be necessary! Also, code shouldn't be a se…
80 character lines are a near-optimum for readability. And command line interfaces are convenient to use via keyboard over remote, possibly high-latency connections, where a more direct interaction becomes clunky. It's also easy to extend: you don't have to change anything in the UX, just add a new command. Moreover a CLI allows for the expression of complex behaviors that are all but impossible to render in a "user-…
Counterpoint: 80 chars is too short for writability. You need to make arbitrary splits and refactors all the time and it ends up hurting readability.
120 is a better sweet spot to strive for in my opinion.