The desktop computer as a gaming rig will never die until I can write game code for consoles or cell phones without a desktop computer being somewhere in the pipeline, as it is ground zero for any game development effort.
Its easier to get set up and develop games on the PC than it is any other platform. As such, it has a much larger independent development community and has more choices when picking games.
Don't even get me started on the cost of indy development on consoles either. Its gotten better in recent years, but you usually still have to buy a platform development kit, which usually isn't cheap.