I think the prisoners dilemma applies very well to bitcoin forks. A game-theoretic rational thinker thinks: If BitCoin players defect the reward is always better for the defector. Because if:
If you cooperate and the other defects, the defector gets the best outcome (In BitCoin that would be retaining all of the original chains coins and amassing the forked coins as well) So it is best to defect.
This though is not the best for you individually or for all players. If all players defect nothing is gained(BitCoin Fails)
This cannot happen to BitCoin easily. Only a controlling force (centralized force) can change the rules so you cannot play the original game. For example government bans.
Superrational thinking assuming the other players thinking is Superrational knows that the worst possibility is when everyone defects. He would automatically cooperate to receive an assured reward although not the best possible. So hard forks seem completely illogical. That is ASSUMING Superrational thinking for all players. When the others thinking is unknown then that is where trust plays a part. Once we convince ourselves this others will cooperate and we make a transaction with bitcoin and all parties receive a reward.
This explains many things. The defecting party (fork supporters) is going aftwe the biggest reward. The cooperating (bitcoin core) players believe enough players will stay on their team to be stronger and thus all cooperating players receive a reward.
Quite amazing how deep the rabbit hole goes. But I believe that BitCoin started a new economic game and is the controlling source of the game. The games is the blockchain and it is the largest and strongest. Fear of weaknesses only should play a part in human error. BitCoin is trusted because computers cannot deviate from the rules. ALTs are fun mini-games within the game so all BitCoin forks just become alts.
Well that's my rant. The Superrational way to play is in a way less greedy. So although I'm late in the game its still fun I believe the segwit2x community is more selfish at a deep level.
Excuse formatting. On mobile
You have to also include short-term and long-term effects as parameters. For instance, not everyone will defect if the other chain does not offer the security (or perceived security) that the current chain does. In fact, most players are likely to remain on the main chain and ensure its survival, unless some true contender came up that challenges the core perception of legacy bitcoin.
However, most players will economically be incentivized to vote for the fork (either directly or in their own heads/wishes), because it provides them with free coins that can be worth something or nothing (but there is a chance of them getting some extra reward). It's true that sometimes this extra reward can come at the price of stability on the main chain, but that would require most users to understand that and it is questionable how many users understand this (the current mainstream bitcoin community is often excited about forks as they see them as "dividends" or "free money", without understanding potential consequences attached to this).
If the consequences of a fork would be that the old chain dies out, even if miners and users are still signaling support for it and will use it, then that could tilt the game and people will feel, in a much more direct way, the consequences of promoting all these forks - it wouldn't be very popular in my opinion, as most people understand that you do not risk all this progress for something uncertain. But how you would go about implementing such a thing is difficult.
Game theory is nice to understand things and certain behavior, but it assumes too much that players are rational or always economically-motivated. There are plenty of people who are more "rebellious" and fighting for ideologies, which throws off a lot of the game-theory stuff. I question how much of the B2X split is currently just ideological and not economically-motivated. Someone who thinks "they have nothing to lose" will make decisions in a very unpredictable way, according to rational thinking.