From Business Insider:
Tim Cook has explained why the iPod Classic had to go. In an on-stage interview at the Wall Street Journal’s technology conference, he said that the only problem was that the company simply couldn’t get the parts to build it.
“We couldn’t get the parts anymore, not anywhere on Earth,” Cook said. “It wasn’t a matter of me swinging the ax, saying ‘what can I kill today?'”
Faced with the decision whether to redesign the outdated product or to end its production, Cook decided not to try and rebuild the iPod Classic.
“The engineering work was massive, and the number of people who wanted it very small. I felt there were reasonable alternatives.”
Apple removed the iPod Classic from sale in September as the online store went down during the iPhone 6 announcement.