I'd be curious to hear from the folks a few years older than I (I started in the later 60s with the GE-635), but my own experiences of having lived through some of it, I personally think it was more to do with all of the systems of the time switching from cards to the Model 28 and later the 33 then Unix or AT&T.  Unix was just one of the systems that we used at the time of the transition from cards.  But the other timesharing systems of those days began to transition to the tty's requirements.  

On Fri, Nov 6, 2020 at 12:27 PM Stephen Clark <sclark46@earthlink.net> wrote:
On 11/6/20 12:13 PM, Adam Thornton wrote:
> I’m going to chime in on pro-80-columns here, because with the text a comfortable size to read (although this is getting less true as my eyes age), I can read an entire 80-column line without having to sweep my eyes back and forth.
>
> I can’t, and never could, do that at 132.
>
> As a consequence, I read much, much faster with 80-column-ish text blocks.
>
> I also think there is something to the “UNIX is verbal” and “UNIX nerds tend to be polyglots often with a surprising amount of liberal arts background of one kind or another,” argument.  That may, however, merely be confirmation bias.
>
> Adam
May have had to do with the first terminal commonly used with UNIX.

The Model 33 printed on 8.5-inch (220 mm) wide paper, supplied on continuous
5-inch (130 mm) diameter rolls and fed via friction (instead of, e.g., tractor
feed). It printed at a fixed 10 characters per inch, and supported 74-character
lines,[13] although 72 characters is often commonly stated.