As always with this discussion, I think it would be very cool if Apple made a console. Is it realistic? Probably not. We'll see though.
Here's my diagnostic on the situation:
The Bad:
Ohhhhh it's SUCH a difficult market to break in to, not to mention that it's crowded already. You'd be stuck with four video-game options instead of three... and figuring out which content is available on what? Another player is just going to confuse things more.
Each added console manufacturer means an exponential increase in titles, features and combinations thereof, available to the consumer... which leads to exponentially more confusion. The consumers will tolerate only so much of this until he/she will draw a line and say "
anything else new from this point out is too much information to process" and "otomatically" block it out. This may or may not be the case with an Apple console... let's call it "GamePod"
The Good:
If PS3 is the impending disaster that everyone says it is, next Christmas would be a great time to release a product. MS won't be ready for another XBox yet, the Wii will still be new, and the PS3 will be losing market/mind-share.
Secondly, (with surprising exception to the Wii) console gaming has been a very static platform, with graphics being the only MAJOR enhancement over the years. Apple has a knack for bringing new ideas to the table, specifically in arenas that have been stagnant for years (think portable music

). That being said, a GamePod could usher in a new era of gaming... that is, if Nintendo & the Wii haven't already done so.
If Apple intends to enter this market, the time to strike is soon.
-Clive