>> I find it odd that there was no mention of working on multiple platforms as an advantage of using OpenGL.

> Because it's really not much of an advantage. Seriously.

> When it comes to a AAA game the big three sellers are Xbox, PS3, and PC, in roughly that order.

That is true. But, AAA games are not all of gaming. In fact, they are decreasing in importance - look at the rise of the Wii and Zynga as just two big examples.

Gaming is growing, and moving from hardcore gamers with AAA games to more casual gamers that use a greater variety of devices. Mobile phones and tablets in particular are becoming very important, as is the web.

DirectX is simply not relevant to any major phone or tablet platform, nor is it relevant to the web. iOS and Android use OpenGL, and the web uses WebGL (which is basically OpenGL ES in JavaScript).

OpenGL, by simply being everywhere that matters, will win the fight.

(Of course major game engines use abstraction layers anyhow - no one chooses just DirectX or just OpenGL.)