I think Appple would(should) take a stand and get into the market. quite frankly i am seriously surprised they havnt already. the market is well and truly right up there alley in things they actualy do good. there PC market never was great, and more niche based for creative fields while MS always centered towards office/casual market. console players are more likely to use an Iphone, Ipod, or Imac by choice than a android/palm os, basic MP3 player, windows based notebook/desktop.
Apple got into the MP3 market in the begining and most people asociate MP3 players with Apple products, they hopped onto the cell phone market a bit late but the first iphone gained a lions share of the market(PDA Phone) very very quickly and is not really being challenged a bit by google while palm and ms are left behind. then they entered the tablet arena.. well they now pwn it.
apple has a proven track record for keeping a secure network with i tunes, the PC market they hold is more geared towards creativity aplications so it would be easy for them to create an OS loosely based off the Iphones and the Mac OS... kinda like the Ipad, but geared to plug and play games mainly with everything else less but still there... as in Mac PC capabilities, using mac apps, KB/mouse full support, actualy giving you console players the computer side of your console rather than a locked OS.
But then Again i think MS should make a new gen console/pc hybrid OS as well, laptop type PC with docking station thats hooked to TV/surround sound, robust enough to run PS3/360 titles(easy as), yet small enough that it can be undocked and taken anywhere... oh wait thats a laptop... sorry just need a better OS to do all the installs quickly and easy... oh wait that already happens... umm ok win 7 now, just need game devs to give complete controler support from the get go! like Portal 2... ok thats all lulz because its true, theres a complete console out already!!!
anyway back to subject... I thin apple should/would fill the void. nintendo has kids and family, MS has hardcore and adult, Apple could fill the middle ground as they are wont to do anyway.