Ha, that too. WoW itself makes up for what, 14 million "PC gamers"?
Why the " " around PC gamers?
The PC is a huge gaming market. Plus there are still some genres that are probably best represented and presented on the PC such as:
Computer strategy game (eg the Total War series, Hearts of Iron etc)
Turn based strategy (eg Civ)
Simulators (which go beyond the Sims. Sid Meier's Railroads! anyone?)
RTS
MMO
And the PC gaming market in non-western nations (such as the places with super competitive Starcraft tournaments) has never been better.
Unless you want to claim the millions of units of Total War or Civ4/5 were sold to the casual gamers of the PC.