Even if it worked, it wouldn't increase the number of good games (Apple is unlikely to start up a first-party team from scratch; they would buy in talent and contract third-parties just as MS has done as game development is not their area of expertise). So it would just dilute the number of exclusive games and take them away from MS and Sony.
That would lead to third-parties dropping the least profitable platform out of X360/PS3/Apple-console/PC (since a four-way porting strategy is ridiculous), and assuming that isn't Apple it would be Sony.
So all Apple entering the market would do is:
i) Decrease the number of games people with a given console can play
ii) Hurt Sony a lot more than Microsoft







