Here is my take on what Apple might do
they want a piece of the trillion dollar pie Sony, MS and Nintendo are currently sharing with. If Apple was to come in they can either go 3 ways
1. build an next gen console, very advanced, No games support and very expensive and bomb hard just like the CDi/3Do
2. Build an next gen console, not so advanced and have small game support and lots of ports, it would sell kinder well but not great. like xbox
3. Build an Next gen console, advanced, competitive and in house game development support and 3rd party support and will explode in the sales and dominate just like the Play station.
There is the possibilities that Apple could get into if they go alone.
Of Course That's Just My Opinion, I Could Be Wrong