Apple quietly discontinued the iPod classic last month, just short of the iconic MP3 player's 13th birthday. Tonight, Apple CEO Tim Cook explained why the company decided to shelve its revolutionary device — it couldn't get the parts any more. Cook, speaking at this evening's WSJD Live event, said on stage that Apple no longer had access to the components necessary to build the 160GB iPod classic. You'd imagine manufacturers would still produce parts for Apple if the company really pushed for them, but Cook said when faced with a dearth of necessary materials, the company felt that it wasn't worth redesigning the venerable device.