CNN — The last time Sony was worth this much on the stock market, Bill Clinton was president and the PlayStation 2 was about to debut on American store shelves. It’s been a rough past two and a half decades for Sony, the 78-year-old company that invented the Walkman and the PlayStation and had long been an icon of consumer electronics. It largely missed the boat on the mobile phone revolution, and while the PlayStation has been profitable, production costs for other electronics have risen while ...