Its quarterly results stunned the tech industry – and its Chinese competitors, who have now been eclipsed in their home market. But reaching the financial pinnacle creates some questions – and even problems – of its ownWhen Apple became the most profitable company in history last week, analysts could hardly contain their excitement.“Stunning”, “outstanding”, “a monster” were some of the analysts’ reactions to numbers showing the Silicon Valley firm had made $18bn (£12bn) in just three months – by selling 34,000 iPhones an hour around the clock from October to December.