There are actual user studies to show that wider text is harder to read. https://baymard.com/blog/line-length-readability
The major difference is that in the era of print, it was pretty logical where a multicolumn wide layout could go like on a newspaper, but in an desktop experience the browser markup is theoretically endless.
I can resize my window easily if I wanted shorter text. Or used ctrl-shift-m on Firefox. But I can't easily make the text longer without userscripts or addons.
> actual user studies to show that wider text is harder to read
That may apply to most people, but not to everyone.
Solution: rotate your monitor 90 degrees, and inform your OS that you have done so. Now your monitor is 1080x1920. You'll actually be amazed how much more of a document fits on screen without sacrificing readability.
The studies go back way earlier than that; there's a reason why they call them "newspaper columns"