The most prominent difference between the two platforms is age. The median age on Reddit has dropped into the teens. I believe that is why the Reddit redesign

The most prominent difference between the two platforms is age. The median age on Reddit has dropped into the teens. I believe that is why the Reddit redesign specifically hid more of the comments - to both hide the rampant low-effort comments, and to discourage kids in high school from commenting in the mobile app. When it comes to social media platforms - less is more. Trying to get literally every human to participate reduces the quality of the conversation.