"Maybe one can argue that knowing the length of a written word has resulted in less people engaging?"

Boy, doesn't that just have the distinctive ring of an uncomfortable truth... at least for some of these cases.

I offer in counterpoint that engagement-focused sites have probably already determined that their content is "less engaging" if it's long enough for a scrollbar to appear at all. If it wasn't for the literal need to stuff 100%+ of the screen with ads, there'd probably be a lot of modern engagement-focused websites doing everything they can to fit on a single screen without scrolling at all.