It hasn't been the "other way around" for a long time, consoles have enjoyed more commercial success compared to PC gaming for years. Nvidia's bread and butter is on PC gaming so their opinion on the matter is biased. You might as well ask the head of Exxon about the benefits of fossil fuel. I don't see any facts to back up their projections, only assumptions that because there is a current trend, that trend will just keep going. The expectation that console sales will remain stagnant over the next few years is plain idiocy. The current generation of consoles have run their course and the new generation of consoles will be out over the next few years. This WILL invigorate sales for them. You have to take Nvidia's opinion with a whole cup of salt, since the first of the next gen offerings, the Wii U, uses parts from their top competitor, AMD. It wouldn't be surprising for Sony and MS to go with them as well, AMD APUs are a nice fit for the needs of console hardware.
Now, PC game sales are rising. Most of the old problems that kept people from PC gaming like expensive hardware and DRM are no longer the issues they once were. One could also point out that the lines between PC and console are greyer than they used to be. Consoles have PC style networking, and services like OnLive present console accessibility for PC gaming, so by 2015 it may not be an issue of PC vs console, but rather general sales across all platforms. Nvidia is just trying to drum up PC business like the floundering fish they seem to be these days.