Outgoing Microsoft CEO Steve Ballmer has revealed in an interview with ZDNet that the company felt forced to manufacture its own Surface line of tablets to better compete against the iPad. Ballmer also said that the company’s decision to make its own hardware gave it the best shot to keep pace in a computer landscape where smartphones and tablets are evolving into the dominant species, even though that meant antagonizing some of its OEM partners that also make Windows-based computers. Ballmer admitted that “nobody ever buys Windows” adding that “they buy Windows PCs” — a surprising statement from the CEO of a company that made its billions over the years mostly through software sales including the Windows OS family and the Office productivity