Here’s the legit answer:
World of Warcraft is fine, it’s experiencing the same/similar player drop off as with any other past expansion as recorded by Neilsen in the past (nothing out of the ordinary), and even with this, is still the 5th highest grossing game in the west. Also Neilsen excludes China/East markets, so wow is potentially even better than shown here.
And incase you have no idea what SuperData is or why you should care about some random chart:
SuperData is the world’s leading provider of market intelligence. SuperData offers quantitative and qualitative insights on free-to-play games, digital console, mobile, PC downloadable, streaming media and gaming video content, eSports, and virtual reality.
In simple terms, they are the definitive tool and rating of gaming market performance and pulls their data from accurate market sources that aren’t privy to just any random joe. Ratings provided by Neilsen is what most industries (i.e. television, etc) use to judge the performance, strength and value of their markets.