Dunno, I feel the opposite way. It's comfortable for me to read one line for longer, then to jump to the next one. I think this is just "what you are used to" - I don't see how either are inherently better or more comfortable to read.

Brain prefers longer lines with less next-line jumps, but people are used otherwise, so they overwork their brain while trying to keep their eye muscles happy.

Where are you pulling this info you're stating like fact from? I can say for sure that it becomes harder for me to accurately jump to the next line of text the longer a line gets. Sometimes missing a line or starting the same line again even makes sense for a handful of words so it's not immediately obvious that I've messed up finding the start of the correct line.

Let me see if I can find the study I've read quite a while ago.

Will link or write another reply if I can succeed. I have no time to look at it right away.

This kind of thing has been an issue for long before computers. Typesetting in newspapers also needed to use line width constraints for better readability. That's why long newspieces are often split across multiple columns. I have never heard if someone who prefers one long line so that's interesting!

On sites with a long line length I will often pop open the dev tools so I can drag them across and squish the page without resizing the whole window.

If long line length was common then browsers would have a similar feature built-in.

> If long line length was common then browsers would have a similar feature built-in.

I wouldn't be so sure. It was common for a long time (and still is on older sites) and browsers never got that feature. They also haven't bothered with a dark/light mode switch even though that is a much simpler feature since the setting is already there.