If you ask me I beleive the PC gaming industry is well alive and kicking. Aside from a rather appaling lack of creativity from Big Game companies, and the plague of "causal" games that is terrorizing us at the moment, we can notice several sucess cases. To name a few I've seen personally: Starcraft 2, tropico 2, sword of the stars, distant worlds, settlers franchise, the sims franchise (as wicked as it may seem), and of course the emergence of indie developers.
Digital distribution free from the claws of publishers is starting to take off at the moment, and its potential for allowing more creative games is something that must be taken into account. Usually publisher approval is the big bottleneck that is making the computer game industry to sitck to tried-and-true formulas, but if you can sell your stuff directly to the end user, who cares if the publishers aren't impressed. Notch's a millionarie and I doubt minecraft would be considered a good idea by any big publisher out there...
A 15% share of the gaming market isn't necessarially something bad if the companies still can turn a profit. We need to take into account that console gaming became a form of mass media. Compare it to hollywood movies if you will, profitable but doesn't necessarially mean there's something good behind all the special effects.
The upside is that now we can act as mac owners and say PC gaming is becoming a more "exclusive" market.
Also for anyone who's moaning that elemental is going to make stardock go bankrupt due to its flop, brad wardell mentioned on the IRC (I think on a dev blog too) that they already are running on black with it. Still doesn't fix his molyneux complex though...