To compete with MS, Sony and Nintendo, I see that they'd need:
1) AAA titles, some sweetening exclusives, and all the major publishers on board.
2) A working network infrastructure with gamer ids of some form that doesn't allow people to post their own scores onto the leadboards...
3) Distribution, unless they go DD only, which cuts out half the gaming market.
4) All the security that goes with that. Apple security so far has been utter poop.
I just don't see the point. Let MS and Sony and Nintendo fight over the small takings from gamers buying and playing games. Media and the hardware it plays on can be Apple's for much cheaper. Joker's post on the cost is very telling, and what I said Sony should have done with Vita with its price - make a convenient little media box that can be carried around and connected to any screen or hifi without needing docking stations and the like. Apple could create an iBox that is an iPhone in a box without a screen, that runs all your same content. Of course iGames are pretty pointless without the touch screen, but anyone wanting to play those sorts of games has their portable device anyway. The media aspect is cheap and easy for Apple to expand without going up against proper consoles. They can sidestep them.