There are two things happening at once here. On the platform side, your replies count as fresh activity on the post, which signals to the algorithm that people are still interested. That signal is part of what keeps the post getting shown to more people. When the replies stop, the activity drops and the algorithm loses interest in pushing it further. On the human side, when people see that no one is responding, the post starts to feel like a closed door. Conversations die when only one side is talking. Why do you think so many creators underestimate how much their own replies affect their reach?