There are games that put out more material than WoW ever did. But before it would be worth the wait. Currently it's just an increasing wait time between each patch, with less and less content. WoW is probably something like the mmo that gets the least love from it's developer out on the market right now.
A good enough game could probably "kill" wow (as in taking let's say75% of their player base over time, just a random number). But none of the games so far have moved far enough away from the "WoW-model" and properly revolutionized the genre.
So yeah, Blizzard will kill WoW. (One could argue that they are doing it right now, no?). And then you'll see a new giant rise to take up the competition with "Titan" But now I have stared into my crystal ball long enough.