One obstacle you have to overcome is that there has to be an investment that is risked by the players. There's not much of a cost to gank someone usually, or it's simply not allowed at all except in a controlled way. One thing that forces people into social cooperation is to protect against the potential for loss. As I understand it, confrontations with other players in EVE Online are dangerous because of that investment of time and/or money. That's part of what makes roguelikes and battle royales so compelling. That said, you have to balance it against being appealing enough to more casual players--how do you encourage investment without making it a boring grind or too expensive?