Originally Posted by
Osmeric
I have a theory about this.
As I've said before, I think the central value proposition of WoW is gratification of the ego. Now, successfully downing challenging content buffs the ego, but failure damages it. So, when a player is confronted with content they (subconsciously) fear they will not be able to handle, they create a defense mechism: they don't put in full effort. Of course this means they DO fail, but they have plausible deniability. They can tell themselves they failed because they didn't make their maximum effort, that it just "wasn't worth it". If they had put in maximum effort and still failed it would have been devastating.
You might find this attitude reprehensible, but I think it's quite real and quite common. And I don't think the devs understand it at all.