And skill, well... let's be honest you really think individual skill really still matters at that level or teamwork for that matter? WoW is really not that hard. Maybe there is a miniscule difference but it's still more about resources and dedication and then who comes up with a good tactic first. Those other guilds are not stupid, not stupid enough to need a week longer to find a tactic that works.
There are now two more Spine kills by Stars and Silent (never heard of Silent). Maybe there is some sort of tactic/trick that the others haven't figured out yet. They better post a video of their Spine kill or maybe they want to see the others sweat a little more ;p.