I was just thinking; maybe large font size, wide margins, and bigger line height may serve to inflate "engagement" because they make it more difficult for a use

I was just thinking; maybe large font size, wide margins, and bigger line height may serve to inflate "engagement" because they make it more difficult for a user to be able to glance at the majority of the page and get a sense of whether it's worth reading. If scrolling and getting a big picture view of an article takes some effort, users may be more likely to either read through the content or scroll slowly. Either way, it's a win for the designers because whatever tracker being employed will provide some fancy charts to convince the suits and ties that their work "increased engagement." It may also get users to look at more ads. All of which will certainly be pitched under the idea that it's accessible. I really hate this if that's true, because the net effect does seem to be that I have to spend more time on a page to determine if the content is garbage or not. With physical books, you could flip through pages and catch things you're interested in by glancing over large areas. The modern web, for whatever reason, is doing quite a bit to prevent that from being possible on our screens without hacking our own browsers to fix the mess.