I found this article very interesting about how the cost of implementing DX10 could ultimately kill PC gaming as we now know it.
Some quotes from the article:
"Mark Rein from Epic Games, who was in charge of the development team on Unreal Engine 3, as well as being responsible for the creation of titles like Unreal Tournament 3 and Gears of War has pointed out the cost problems of developing DX10 games. The price of a higher end DX10 compatible PC graphics card does not compare favourably to the price of a console, in some extreme cases you will pay double the amount for a graphics card than you would for a console."
"id Software has declared the same outcome. The PC will become second fiddle to the console; their programmers will focus on developing games primarily for the console and then port them to the PC (maybe). They are so convinced that this is the way to go that they have attached Xbox 360 controllers to every single PC at id, to get their programmers in the console mindset. This move reflects their new philosophy; where once they focused on pushing graphics cards to the utmost limit, now they will focus on gameplay, and ensuring the games will run on any system, not just high end systems."
"Making a game that is playable on the console requires sacrifices to be made on the PC version, as no company can afford to design every part of the game twice, once for the console and once for the PC. It makes economic sense to develop as much code as possible in tandem, so that it works on both systems, with a bit of time at the end to see if any extras can be added to the PC version."
"Another likely casualty of porting to PC was Oblivion's A.I, named Radiant AI. While Bethesda was having problems with certain Non-Player Character interactions, one can't help but wonder if the AI was lobotomized to make it play well on the Xbox 360."
PC Gaming: Why I'll Never Console Myself with Second Best