It will die eventually, even if that takes decades.
Everquest 1 and Ultima still have servers up.
At this rate, I see WoW existing (with slowly declining subs) for at least another 5-6 years. Which in my opinion, is not "dying". WoD has proven that an expansion can significantly boost the number of players. I'm sure it will drop off again in the next 6 months or so, but obviously players are still passionate about the game, so it's not going down without a fight.
Honestly, I would be perfectly satisfied if Blizzard purposefully killed WoW in 4 or 5 years and created a WoW 2 with a fully modernized engine, graphics and interface.
World of Warcraft: Too Big to Fail. Does it qualify for government bailouts? Hurrhurr.
"You hurt me long ago; my wounds bled for years. Now you are back, but I am not the same."
It will die some day but it would mean that other, better MMO took players.
Certainly. But I think the idea of starting fresh and it being a new game experience would be attractive to a lot of people. It might seem less intimidating. New people are already intimidated by the leveling.
BUT if they just ported everything over they would pretty much have to keep pandas in the game, which is unacceptable.