sigh... The JIT engine in your graphics driver stack will contain millions of lines of heavily-licensed, patent-riddled code.

But that doesn't stop you as a developer from freely writing a 3D game that runs on it.

Same here. Think of it as a device driver. Ideally we'll open-source everything eventually, but anyone who's ever been involved in real-world commercial software development will understand that things aren't always quite that idyllic when you're building a business around it.