I'm glad you've ditched the attitude. It allows for a more civil discussion, and makes the sides of the argument much easier to comprehend. That said, I never implied that individual player skill is not important, but that's not what this is about. What this discussion pertains to is the difficulty of content along the middle ground. As I mentioned before, a group of skilled players can and will trivialize how challenging the content is, but that does not increase or decrease the difficulty of it. At the EX level, the content stops playing around and lets players know that knowledge of mechanics, obeying them, and group coordination are required to clear it. It also lets them know that if they do not know how to play their job properly and how their skills tie together, they will not be pulling their weight, and avoiding enrage will be difficult. The difficulty of any particular EX encounter is set by how many mistakes are allowed to be made and the clear still be possible. EX encounters become easier over time due to ilv increases, which allow more mistakes to happen along with the party causing more damage overall. The Echo by itself also makes the encounter less difficult each time the party wipes.
Nearly every person is capable of overcoming a challenge. That is what I feel is very important to take to heart. I don't think there is a single player who decides to participate in an EX encounter who does not think there will be challenges that will have to be overcome. That just confirms that middle ground content does exist, because in nearly all the content below the EX level, players don't have to worry about this at all. They will clear those duties one way or the other.The vast majority of players are unable to work effectively as a team. Even when taught how to do fights - even when provided with callouts and markers, most of them simply cannot or will not do it. There are also those that have the potential to improve to that degree but become demoralized and ultimately give up instead of continuing to push themselves. Additionally, it is important to consider that what is difficult for one person might not be difficult for another, which is why we use the majority as the basis for determining the actual difficulty of content relative to player-base. A minority being able to overcome a challenge does not mean everyone can, or that they would be willing to try to begin with.
It's a team effort. Regardless if you feel it is your responsibility or not, you win or lose as a team. If someone screws up a mechanic that wipes the whole group, you can pin the blame on that one player, but this doesn't accomplish anything. When everyone helps this player understand their role in the mechanic they fail, and if that player communicates what exactly it is they do not understand to the others, the result more often than not is success. Especially opposed to just pointing the finger at them, and telling them they suck, or get better. A good example of this is when a player is confused on their clock position, or where a healer is supposed to take their stack marker. If it is unclear, wipes will happen. Help them to understand, and the content won't be harder than it needs to be.Now, to your last point; the failings of others are not my responsibility. I'll gladly go out of my way to teach people that are willing to learn, but the ones that can't or won't, which does sadly appear to be the majority, are not problem. If being unwilling to tolerate those that won't better themselves means I'm "not a good team-player," that's fine. My opinion hasn't stopped me from clearing content, and it certainly won't magically start hindering me now.