There may be thousands of people who want WoW to die, but there are millions who just bought Cata.. WoW isn't going anywhere for a while.
Rift has the potential to be a great game. Will is be as successful as WoW? I doubt it, but time will tell. They have done a good job marketing it and creating a buzz around the VIP beta keys to get people looking at the game and dying to play it which will hopefully carry over to launch.
Is Rift the WoW killer? Is the Android OS the iPhone killer? NO. It may take a slice of the pie, but it won't get close to killing it. The only thing that will kill WoW is time. Games have slowly gotten more advanced and will continue to do so. WoW will slowly fade out over the years, but nothing in particular will "kill" it except for time itself.
"What MMO do you think will be the survivor of time, and what about the MMO (specifically) makes you think this?"
EQ is the survivor of time.. They will ALL eventually die, but EQ has held on like a champ.