Revenue from 14 goes into a variety of things like new content for 14, it goes into developing new games (funding for this would also come from other games that had been released) without developing new games the company would die out.

ARR probably had more content than hw and more dungeons being added in earlier patches than the later ones, you have to realize as well during probably the first year and a half of the game they were trying to recover from the train wreck of 1.0 and not actively developing any expansion content, I think 1.0 nearly ruined the company