A decline of game quality =/= the decline of PC gaming. It's just a fact that many developers try to create games for all major platforms, and in doing so limiting themselves to console standards. That's disappointing, even if complaints about it may be exaggerated, but it doesn't mean PC gaming is declining or dying at all. I can't see consoles ever killing off PC gaming until they're genuinely better technology for playing games on, and they're way behind PC right now by that standard.
I'd add that I don't think game quality is actually declining, but rather lagging a bit and not improving as fast as it could.
The problem with this kind of debate it's that it's ultimately just partisan talk.
PC gaming isn't "dying", but the relevance of the PC gaming platform in the hardcoe game market is fading. When games like TES generate 80%+ (sink that number in your brain, and ponder it) on FRIGGIN CONSOLES, you know something is off.
Budgets for videogames skyrocketed. In a world where developing Skyrim costs hundreds of times as much as what developing Daggerfall probably did, the PC gaming community, for a variety of reasons - from piracy to "who pays games 60$ lol" to Steam sales to size - doesn't sustain a market anymore.
The Witcher 2, the biggest PC exclusive of the year (barring Blizzard games that still didn't sell much more in the West), reached one million sales in six months. Uncharted 3 and Gears of War 3, two big console exclusive, shipped almost 4 million units EACH in the first WEEK.
We're not talking about change. The difference in income is insane. And those sales are full price.
I like PC gaming as much as everyone else, but you can't be blind to this. TODAY, the things who make money on PC are 1) MMO and 2) Facebook games. Like it or not, we've come to this.