>>70541481People attracted to a particular game will leave when said game is over.
What keeps people around is the "meta narrative", the overall "story" your character is selling.
Let me give you an example: I join a raid, and check the person 10 seconds or so before I close it.
One person says: "welcome raiders" and moves back to the game. I leave
The other person, introduces her self, and does a small blurb, and then hits me with "and my dream is to be an idol" or " my goal is to reach master rank at X game"
"Ah! Here so this is the plot. Maybe I will watch." I will still close it in a few minutes anyway since I'm probably tired, but I will sub, and check it again later.
You want retention? Give people a reason to keep you watching. Tell them why they should root for you.