One of the things that I've noticed as I reflect on roleplaying games is that there's a very big difference between how I see people play them versus video games.
The biggest difference comes in the form of the cooperative methods used in tabletop roleplaying versus video games.
Most video games have a fairly distinct basis for cooperative modes; a shared objective that is openly stated and largely shared between the players. Even a game like Divinity: Original Sin or its sequel (Divinity: Original Sin 2, which raises questions about exactly how many sins can be original), which promotes more individual agency than many other video games, still has a fixed plot that it expects its players to follow, with largely arbitrary goals along the way.
Other video games tend to work this way too, though there are rare exceptions, namely sandbox games where players are generally encouraged to find their own way. Many MMORPGs contain elements of this, as do games like Minecraft.
In these worlds, players generally work toward an individual goal, using emergent systems that don't prescribe a particular objective, but usually foster a particular type of play.
Still, many people think of these games as generally a cooperative experience. However, there's a pretty big difference between cooperative as in "We're raiding this dungeon together" and "I'm building in the same town as you."
Really, the former is cooperation, and the later is toleration.
Cooperation on the Tabletop
I feel like in a lot of tabletop roleplaying, the game leans toward mutual toleration, rather than cooperation.
This isn't to say that you don't have adventures and short-term goals that players work toward together, but rather that each player's character has different motives and goals.
One of the interesting things about this is that some of the best games that I've ever run or played in have been focused on experiences that generally may not be deemed "interesting", but which wind up having these shared cooperative long-term goals.
One of the examples of this is Fantasy Flight Games' Only War (affiliate link).
While I'm pretty big on military-related themes in my games and science-fiction, the world of Warhammer 40,000 is not one that I particularly would associate with deep roleplaying. It's sort of the WWE wrestling or American football of tabletop roleplaying settings; lots of big muscular dudes running around and hitting each other, and while there may be drama it's probably staged and overwrought.
However, I don't think I ever had as much fun or as deep a connection to my fellow players' characters as I have in the grim darkness of the future.
Why?
We had true cooperation.
That's not to say that the backbiting of some of my Shadowrun games or Paranoia has no place in gaming, but in Only War our only focus was staying alive.
I reserve the right to share any songs that pop into my head.
Of course, that goal would change to reflect whatever short-term concerns were going on. One hilariously zany one-shot I played in had a bunch of soldiers trying to cover up their general ineptitude and corruption as the brass was coming around not only was a barrel of laughs but led to the creation of memorable characters who would go on to appear in future stories again and again.
What worked well there is that all the characters had a meaningful reason to stick together, an extrinsic shared goal.
By comparison, lots of other games that have stalled out find themselves dealing with the consequences of having many characters, each of which have their own complex motives; this is not inherently bad, but leads to fragmenting.
By comparison, the characters I've seen in Only War are no less complicated than those of any other game, but they're subordinate to a greater goal and objective.
Applications for Genship Exiles
I've been working on Genship Exiles for a while, and while I don't want to spoil too much (in part because it's still in the "Everything will change" stage of development), I do have a few things pinned down.
Genship Exiles works on a stripped down and rebuilt version of Hammercalled. It's built from the ground up for cooperative, storytelling driven play, and Hammercalled itself leans toward expedient storytelling, so we'll see how much better it can get.
One of the things that I've known I wanted for Genship Exiles for a long time is to have characters defined by abstract affinities; someone might be defined by Power, for instance, as their primary aspect, which governs a whole lot of connections.
Each character gets a meaningful boost to their core affinity, but they also form bonds with others.
These bonds function at one of three levels: minor, major, or critical. A minor bond is a work acquaintance or distant friend. A major bond is a relative or inner-circle friend. A critical bond is a mentor, spouse, or child. When a character is working directly alongside someone else, they gain their standard bond level, but when they're not around the bond is reduced by one level.
The purpose for this is to let characters have a built-in cooperation system that's not tied to mechanics, and encourage abstracting out some of the mechanics. Players working as a group actually have that group become the more important mechanical element ("With X here, we're really good at Y!"), changing the interaction from being focused primarily on players as individuals with the GM to being the group as a whole with the GM.
We'll see how exactly this pans out, but I'm relatively confident that it, when combined with some other things, will create an interesting and unique experience (coughnowarrantycough) as far as roleplaying goes.
Wrapping Up
Basically, if you want people to cooperate, give them a reason to stick together. I've been in games with really high character turnover that still manage to keep the feel of a shared goal, but I've seen games where players and characters have been together for years and there's just not connection, no chemistry.
As a GM, or as a player, you can work toward this by establishing some sort of group identity, though the methods for doing so are perhaps worthy of a separate examination in and of themselves.