Microsoft is hanging onto a place in the mobile business by an increasingly thin thread, yet despite a 73% year-on-year fall in handset sales in the first quarter, it still refuses to abandon its disastrous Nokia devices acquisition. Indeed, recent reports indicate it is planning a major launch of Windows 10 mobile hardware, though not until the start of 2017, by which time it may be too late. The usually clear-sighted CEO Satya Nadella demonstrates muddled thinking when it comes to smartphones. He has scarcely hidden his lack of support for his predecessor’s decision to buy Nokia’s handset business, and has slashed its headcount and product range, but he has not shut it down. He argues that Windows 10 needs…