My spelling is terrible. Prefer numbers anyways.

A lot of this makes since, but we don't actually know what force or forces invaded Earth (although I hear someone [i]could[/i] tell us...). This is a fault on the story writers for trying to make us assume that the forces we fight in destiny play a large part in the collapse. Despite this, they were supposedly more organized than we see in game, so that's what I go off of. You also have to remember that destiny the game takes place after the key battles and significant events of the collapse. Our story starts in the epilogue of the collapse, and after a supposedly significant battle that saw major casualties on all sides. Now, I've never been a fan of the enemies we fight in destiny. Some of my first posts on this forum were making fun of them. However, credit where it's due: each of these forces would be terrifying to the explorers and a slightly more advanced version of our current society. Military instalations were never properly built to keep up with tech advancements, focus was more on spreading across the stars than getting ready to hold out against an attacking force... so on and so forth. They caught humanity while we were looking the other way. No mention of organized counter attacks or use of nuclear weapons either, so they would have had to attack while the world was 100% unprepared and inattentive. As such, once the primary military forces were dealt with, civilian militias and gangs would lack the large scale coordination and long term supplies to pose a significant threat. They would have no chance to counter attack because they would barely be able to hold a fallback position or base of operations. Now for the aliens: each offers a unique flavor when taking all of the previous factors into account. The fallen scrap yard pirates are loose in large scale organization, but function perfectly as shock troopers and in siege based warfare. Large, intimidating, moble, and speaking a harsh language, fear and confusion would play well into their hands. Their ships are more mobile and modular than those of human forces, and all fallen vehicles use weapons that can potentially immobilize whatever they can't destroy. They're leaders operate to the rear of the front lines, giving them easy access to reports on current assaults. Also remember that humans were still using ballistic weapons, which would eventuallyrun it of ammo where as fallen weapons can continue to function. I don't like the hive. They're like power ranger bad guys to me, making up rules as they go along. But you brought up their greatest advantage: claw and sword. Hive melee fighters are either lean and nibble, or massive and broad. They also have a skill of getting into locked down facilities. A well fortified position can sustain ranged combat and hold off advancements for weeks or even months, yet can be cleared out in a matter of hours if the right hive can get in. The hive have numbers and a zealot like devotion to death, so their presence alone could demoralize a vast majority of a human fighting force. The vex are as much of military thought as a terminator: walk, shoot, repeat. They're advantage is in their strength and technology, not their tactics. They only use one because, if fighting humans, they only need one: advance. Even the smallest of vex units are resistant to conventional ballistic weapons. And if the head is damaged, the unit will frenzy and cause droves more damage to the enemy. Larger vex units are equipped with a shield, rendering them nearly invulnerable to all small arms fire. Even if the shield is breached, they're heavily armored and able to recharge their shields. Not the most tactical enemy, but still a significant threat. I don't think the cabal invaded Earth, so I'm not going to talk about them. In short, I like star wars.

I agree, there will always be people that try to take advantage of a bad situation just as there will others who are trying to get by the best they can. Street gangs come to mind in this situation. They're organized to an extent, that would allow them to control general areas. They would also hold the upper hand in control over their local population due to combined firepower and store of supplies from raids no doubt led by people well practiced in the understanding of needs for both their grunts and drug suppliers. From here, civilians in debt to these gangs for any reason can be conscripted at gun-gun-point to serve as cannon fodder. So on and so forth... There is an issue though: They are still just a Simi-organized militant force of civilians. We are led to belive that the darkness is an unrelenting force of well organized military and zealot forces that will stop at nothing to wipe out humanity. Civilian forces may have an organization focused enough to hold off the darkness from a fortified position, but they are not a military. Humans still use ballistic ammo which will run out eventually if pressed hard enough. So in the end, they are out manned and out gunned. You wouldn't see people trying to take advantage of others during the events of collapse because it's unlikely that you would see other people out in the open. Those that do attempt such things would be giving away their positions to the invading forces and would not survive. The risk is too great to get out in the open like that in this situation.

I do wish there was more information on what happened during the collapse. Even if documented records of the event were lost, we know for a fact that there are stories and likely witness testimonies that we may never get to hear. Like I said, I feel we begin in the epilogue of the main story. But while we have no direct answers of the collapse itself, we can find details surrounding the event. Mainly: -the event was beyond human control. -human responce was reactionary and likely delayed. -the city becomes the last human settlement. -the traveler offers a tool rather than knowledge for the first time as it's last decision. -this tool provides strength and revives lost ranks. -a large battle is fought in defense of the city. These events suggest outside interference as the initial cause of the collapse, the end result of which was likely an invading, or at the least shock, force. During the events of the collapse, we know that the last city becomes the last remaining human settlement. This implies that all other settlements were either seized or destroyed. For this to have happened, all militaries across the world would have needed to be quickly struck down to prevent any chance to fortify positions or launch a counter attack. Due to global communications, this would have needed to be done in a matter of days or weeks at the most. Once the militaries are dealt with, an invading force is then free to fire on civilian populations. Based on the force needed to counter all militaries and the lack of defenses for civilian settlements, this would take days. If the last city is really the last city for 1000 or so years (the opposite of what you'd expect from a society seeking to recover and expand), it would have a well established supply production and scavenging line, government, and law enforcement (which are carried out largely by the tower factions). If we are to believe the collapse led to outcome of ghosts, the last city, and guardians, it must be assumed that the events would have happened too quickly for any other location to survive. Some people will try to take advantage of any situation, but it would take months or even years and the development of routes between multiple settlements before moral codes would break down to a point that a man uses his family as bait (unless they were that heartless to begin with, in which they likely would have tried to leave their family behind as a distraction to run for safety). The time span during the collapse is too short for situations like this to occur, and a city that served as the only remaining settlement of humanity for 1000 years would never tolerate these types of actions. If it did, then the city would have fallen into anarchy and humanity would have lost its last chance at survival.