Every bit of every thread must show in the main feed, or it needs to be painfully obvious that not all the content is shown. You know why? Because you can post in the main feed. It's stupid when someone posts a question, you answer it, then you see later that someone already answered the question but you have to actually open the thread and click a bunch of stupid little buttons to actually see the entire content. This is also incredibly unhelpful for anyone who might have a similar question or some interest in the answer. The answer may not show up in the main feed because it's in a reply to a comment. It's not obvious that the question has been answered or even commented on!