If the titan rumors are true and it has a link to wow as in transfer toon progress then i guess wow wont die as it will live on in blizzards new MMO in a way, but at same time the new mmo will kill it.
If that fails wow will die when the sub numbers fall low enough that blizzard see's no point in leaving it running.
As for when its no longer to mmo that will happen sooner than when it shuts down. eventually when not many are playing another mmo will have higher sub numbers making the new mmo #1.