I get your point, but i think the main reason for using 80 character line length nowadays is that its more readable. Books use often line lenght of about 60 characters for this reason.
I am in strong agreement that there should be a character limit, and I'm even convinced that my 180 character wide terminal is longer than what would be an appropriate limit. But 80 characters is less than half of that, and so I'm not convinced that honoring a default 80 character limit is going to make anything more readable, more likely that it will just result in me turning up my font size so there is not so much unused space on my screen.
I think it's also true that most people use a larger than 80 character wide terminal today.
I guess the point is, without getting hung up on this knob in particular, that fewer knobs is pretty much always better; at least that was the central theme of the issue where I got the idea that Rufo maintainer team has this outlook: https://github.com/ruby-formatter/rufo/issues/2
But I also have come to like prettier's approach. At least, I did last time I used it a year or two back. Almost no configuration, no bikeshedding, it just reformats your js code and doesn't sweat the rest. It's not having every style exactly how I like it, but it's much nicer than the eslint/jshint/etc hell I used to configure. Of course to some extent these tools solve some different problems but I didn't really feel much of a need to keep eslint around once prettier started enforcing its standards.
Point being, everyone has very different preferences and work practices. Team standards are going to be very different from team to team but standards do help reduce cognitive overhead on wondering if line lengths or other styles need to be different.