Because they spend a huge amount of development time on PvP as is? In reality that time would likely translate to one dungeon, if that. If we're going by percentages, then high end raiding content isn't worth developing, but as know that isn't the case since the game has to appeal to a wide audience. I for know that there's a niche audience that loves the PvP, and I wouldn't want to take that away from them. Lately it seems like there's been a large influx of "I don't like it so it should be removed" and it seems rather silly.