First off, the PC has not been the primary gaming console in a long itme, if ever. Console game sales are far and away above PC game sales.
As far as PC game sales dying, people have been predicting the death of PC gaming for a long, long time. It has it's cycles, and has some bad years, but there are things that can be done on PCs that just can not be easily done on a console (yet). Also factor in the cost of entry into the market. With the current (and past) gens of consoles, you have to pay the console maker for rights to make your game. The PC world does not have that restriction at all. That factor alone will keep PC gaming alive for years to come.