There are reasons all systems and groups fail eventually. Why everything has an end. The main reason with systems and policy holders like Governments is that they will eventually no longer serve the needs of their people. It becomes unnecessary and restrictive instead of enabling its populace. There are several key causes of these failures, at least I see them as such.
The first is when the system refuses or fails to evolve to a new environment. This is not as much a problem with Governments where the people force them to evolve with the times, however it does still affect them from time to time. It is more prevalent with smaller systems like businesses or Xbox Live clans. The environment is always changing. Situations rise and fall. Technologies are ushered in and become obsolete. What may have served a populace or the system itself well enough in the past will not serve it as well or at all in the present and future. Ultra conservative systems will find themselves ill-equipped to deal with current or future situations because they choose not to progress, only wishing to do "what has worked before". Because they cannot or will not evolve, they will depreciate and die out as their people become discontent. I know that if my former Xbox Live clan didn't exclusively hold to this philosophy, it wouldn't be one of the oldest Halo clans out there.
Another cause is when a system is only led by the vision of a single person or a small group. I have a saying, "Anything led by one man's vision is doomed to fail". I say this because that small group or single person cannot possibly understand and hold the same values as those of the group as a whole. The few cannot see from the perspective of the many. And the elite in particular cannot see from the viewpoint of the oppressed. In short, their vision is too narrow and blinded to see the needs of the people for long. When it comes down to one person in particular, that single person carries with him his own personal values, beliefs, and opinions. And he acts on those opinions. It is almost guaranteed that their policies will not resonate with the system forever. There will come a time when the opinions of the rest differ from that of the policies. And eventually schisms will form and the system will crumble. However, if a system is led by many, from all demographics, that system knows its needs and the needs of its people better than than that of one led by a few. It holds a more realistic concept because the system is led by its people, not a handful that are removed from the picture. I think this is the major issue with the US government in particular. It is ran exclusively by the few and the powerful. Their view of the entire situation is different than that of the general public. It is also colored by the Power Elite culture which sees the lower masses as exactly that, lower. They see them as there to support and serve themselves. A government should exist for its people, people don't exist to be governed. If a government were to be ran by many, it would start to see itself as existing for the people, not the people for them. The US government, I think has forgotten that since the Founding Fathers. And with a population of over 300,000 governed by the views of a couple hundred, I'm not surprised. It becomes even worse that the US has a political leader and figurehead in a single person exclusively holding a third of the political power. If the wrong person were to ever be elected, it would be the death knell.
A third cause is one that almost every Revolution and Uprising and Schism, etc has made, even the Founding Fathers. And I believe it is a fundamental reason why Humanity has so many failed systems corrupted through greed and power hunger, etc. And it is a reason why we still have so many failings and vices that have never disappeared. It is the fact that after every uprising, every revolution, and every schism, the person or group that led the creation of a new system, takes leadership of it once created. This is a fundamental flaw because, in essence, they came from the old system. No matter their intentions, beliefs, or values, something remains of the old system. They are fundamentally corrupted because they created their idea in a system that was corrupt. Something always remains of the past that they refuse to give up, and it causes the new system to hold those corrupt ideas and values as well. There is a work around however. If those Revolutionaries never assumed leadership, but instead appointed those they know carry the values that the new system needs to have, the new system could be free of the old. The old cannot lead the new, but it can influence and produce the new. However, it must realize what in itself is corrupt in order to do so. Should I ever find myself in a Revolutionary position, I know I will never assume leadership of what follows, and instead let the new be led by the new. Each of us, we're part of the old. We are corrupted with the same core as the old, because we grew up in it. Our ideas of the New formed while in the old. Something of the old will always influence our policies in the new. However, we can teach and inspire people who aren't yet influenced by previous ideas, even if we carry them ourselves. I will go more into depth about that on a later date perhaps. Personally, I wouldn't lead. I would advise for those who do lead, however. And in that way, I could move that society that much closer towards ridding itself of even core "Human flaws" like greed and over consumption. Because while we personally don't wish to give them up, our descendants and future generations may find that they are finally willing to live without them.