Because there isn't one, and wont be anything new till the expansion. PvP and WvW are in maintenance mode, they dont care about us and want this game to be single-player open world PvE content with the occasional world boss. Note that the word "Soloable" is in the road-map quite a bit. And somehow it's been like this for 5 years and people still play it. Oh wait, because there are a bunch of changes over the years. Of course open/living world content is going to be soloable, if you try to take that as an indicator the game is dying or that they are catering to certain people, no. Just more of the same.