The problem is not the hardware, most of the hardware is quite standard (beside a few things like the cell processor). But what counts is the software. Yes Apple would make a great UI and it would be slick, but they don't have the gaming clout behind them, no big name hits that are funded by Sony or MS.
BUT I think we are seeing the sleeper console pop up, and fill a niche that no one else has taken yet. The casual gamer. Is there a market for a gaming console that has many of the same features of the big boys but designed for people who are not hard core gamers? Some may say the Wii is one, but that really is more for the younger crowd although some games are mature.
What I think we have now is a console that is for the casual gamers and for instant gratification. A console where you don't need to leave your seat to play new games. Imagine if you will, a console with the game library like the iPod Touch / iPhone; available to you at an instant for instant purchases and instant playing. Games that range in the $4.99 to $9.99 range, but many cheaper, and a few higher. Maybe the games are not as complex, or indepth, but fun none-the-less. May I introduce to you, the new, AppleTV. Apple's entry into the console market.