I do not think people stop scrolling because something is perfectly designed.
At least from what I have been noticing, people stop when something feels slightly different from the pattern around it. A line sounds more honest. A visual feels less expected. A post names a thought they already had but had not put into words.
The scroll feels like a quick test. Is this for me? Do I understand it fast enough? Is there a reason to give it one more second?
I am still learning how to create that moment, but I am starting to see that the best content usually gives people a clear way in.
Not a trick. Just a small reason to stay.