I really like your ideas they sound falloutish. If the collapse really happened today I think the world would be like how it was in elysium the people of the city would be like the ones on the station and those left behind would descend into chaos and rightfully so... they should portray the darker side of humanity that would most definitely be a side effect to loosing absolutely everything. It's sad that you put more thought and effort into this then the entire story development team thus far (that we know of). Destiny really needs to play both sides of the story people in the tower seem to be rife with confidence and hope but I know myself if I lived in the last human city under constant threat I would be acting like if I was on the walking dead tv show.