... I think that in a decentralized system, one cannot talk (by definition) of a "community" because we are supposed to have an eco system of non-colluding entities, contrary to most open source software, for instance, where "community", "cooperation" and "leadership" have a meaning. The whole idea of a decentralized system is to have antagonist entities that cannot collude over any change, because any change is in the advantage of some and the disadvantage of others, given that it is a system with on-purpose scarcity and competition. You cannot have a "community" in a competitive free market either ; every form of significant collusion is called a cartel.
The central definition of "community" is like-mindedness. The fact that competitors are opposing forces doesn't negate that they have certain like-minded goals, aspirations, and views. While the ecosystem may involve you vs me, we share the same interest that we want Bitcoin to be a success.
Not necessarily. We could both be interested in bitcoin as a tool to take wealth from one another. Whether that goes through the "success" of bitcoin or not, is a different matter. For instance, I may want bitcoin to fail if I can make you believe that it will be a success, and I short it so that you accept my short at interesting prices. Bitcoin is then a useful tool to extract wealth from you to me.
Another example: as a miner, I could spam the blocks full so that the fees go very high, because people are locked into bitcoin with big fortunes, and they have to transact for their fortunes to mean something. In the long run, this could kill bitcoin, but I don't care as a miner, bitcoin only has to last the life time of my hardware investment, and by squeezing out the maximum of users now, I make more than if bitcoin were to be successful long term (where I'm not invested). For the moment, that's still not the right attitude because the block reward is still larger than the fees, but if the fees become the dominant revenue of a miner, it would be logical for the miner to squeeze out the maximum of the users, rather than the long term health of bitcoin. For instance, if you can multiply the fee by 10 while you make the market price drop by 4, you are winning.
But, on the other hand, if I'm a hodler, I might want bitcoin to be adopted as much as I can, to sell my coins to the largest public of greater fools thinkable, and so I may be rooting for its success.
Bitcoin is just a piece on the chess board, in the game of taking away wealth of your peers into your pocket ; the only "common interest" we have in such a system, is to rip off one another. This is exactly because bitcoin (like most crypto) is
a speculative asset, which is exactly that: a tool to rip off peers in essentially a zero-sum game. Whether that tool thrives or breaks when doing so, is of lesser importance. Its thriving or breaking can even be part of the strategies involved.
Not all compromise is collusion (which by definition involves secretiveness and/or deceit).
Maybe I'm using the wrong word, but I thought that cartel formation, even in the open, was a form of collusion. That is:
a kind of temporary agreement between actors in a game, to bundle forces to get advantage over others, if that is a beneficial way of doing. For instance, the OPEC cartel is/was a collusion between oil providers in order to screw the open competition in the oil market and screw the customers, but there was no secretiveness or deceit in that.