Treatment in media is definitely one big factor shadowing PC gaming...
Console games are favored in media pretty much always.
Good example is that it's always PC games which are accused of increasing violence! But how often have you seen consoles accused of that despite all kind of beat em ups have been basic games of most consoles from start?
Take Crysis for example. All elitist, all pumped up to the nines with the best looking graphics and all the hardcore PC gamers drooling over it.
Then it gets released. Nothing can run...
If Crytek had not been so blinded by visuals, they could have downgraded the graphics of the game (I'm guessing) to run it on Xbox 360 and PS3.
But no. Had to be exclusively PC, had to only be playable on a Tri-SLi XXX Uber L33T Gaming Xtrem-o-vision computer. Had to be marginalised to a point of no return.
Consoles are and will be always that "lowest denominator" so there's no point in making PC games so that they can run directly equally well in them because that will mean low resolution textures and lot of such compromises and limitations.
But what is damaging PC gaming is definitely this hyping of need for Crossfire/SLI and games made to them incited by graphic card makers... and what's worse then these claimed to be "PC gaming enthusiasts" playing parrot with that in everywhere!
I don't see why any rational people should get excited about need to buy second expensive, power hogging, hot running component. And miraculously for human specie majority of people acts rationally in that.
Gameplay, content and story should be higher on priority instead of "best" graphics!
Good example is Max Payne 2, when it was released it run reasonably well on average PCs of time and graphics are still decent today. But gameplay and story haven't deteriorirated a day. (if you don't have it I strongly suggest to get it)
And like Peter450 said sloppiness of code definitely plays big part in insane hardware requirements. And I don't think Microsoft is helping any with their idea about advanced OS being one which hogs as much power and resources as it can.
Maker of 3DMarks, Futuremark (former MadOnion) which itself was originally "spin off" of Remedy Entertainment (Max Payne games) has actually founded own "spin off" called Futuremark Games Studio. While Futuremark is called with such "fond" names like "Enslaver of new hardware" they know how different hardware behaves and they're intending to make game engines such that they scale well meaning reasonably good graphics also on moderate PCs.
So let's hope that they'll succeed well.