1) Marketshare. Too low. 2) Of this marketshare, an overwhelming amount is laptops. Not ideal for games. 3) Of these laptops, the overwhelming amount are the cheapest models. Discrete GPUs are commonly missing. 4) Until recently, the GFX API on OS X was antique. Barely competitive with D3D9. 5) Apple's OGL implementation is well known to be inefficient. Windows doesn't have a real one, instead its implemented by the GPU driver. Windows machines can commonly handle instructions sets the hardware cannot. Its the inverse on OS X, where you commonly have hardware features you cannot reach due to the software. 6) OGL 2.x is well known to be quite messy to work with, and this until very recently is all OS X supported. 7) Because of all of the above, many games are written in D3D. Especially games which require their own engine. Good D3D developers are therefore easy to find. Good OGL developers are not. The net result is basically that making games for OS X meant making games for a minority market, with on average weaker computers, using older and less efficient APIs and inferior developers. When graphics is a significant contributor in marketing - especially in AAA titles - its simply is a no-go.