I've noticed also that I don't like to read text that starts on the left of the screen.
The solution that works for me is to install a sidebar (on Firefox, AiOS add-on) and if text is too wide or starts too much on the left, I enable and resize sidebar accordingly :)
Yes but to optimize for larger screens, the correct thing to do is to scale everything up (fonts, spacing, etc) in a responsive manner.
The amount of text content per line wouldn't change much, it would just fill up the screen better instead of using the same tiny font size you'd use for a 13inch screen @ 1080p on a 32" 4K display.
When lines get longer you either have to increase the leading, or font size, or shorten the lines to retain readability. Personally I hate having to detach every other tab from the browser just to change to width to something that's readable. In that sense I much prefer the content to have a maximum width beyond a certain viewport width because it's the only viable option to still have text that is readable.
(It's one of the things I loved about the design style of Windows 8 apps that has been lost in the Windows 8 hate, and admittedly was a part of the Windows 8 hate, because people don't respect a good horizontal scroll of columnar reading material, sigh.)
Totally agreed on your other points (particularly about animations on selection) but as the article mentions, eye tracking repeatedly shows people have trouble reading very wide text. Also many people use large monitors to have multiple windows, rather than a single window maximised.