It is tricky to manage any large company. The more tricky problem for Microsoft is that it heavily depends on old business models. A significant portion of Microsoft profit comes from Windows and Office. Other companies, like Google, can offer competitive products almost for free. That could happen eventually. It won't take Google too much efforts to provide a desktop version of Android and Office-like product. Even at several billion dollars R&D cost, it is still much cheaper than Motorola purchase.

Microsoft enterprise business is hugely competitive. But other than that, it is hard to achieve meaningful profit margin (xbox may earn couple of billions, internet services always lose money, Nokia probably break even for next few years). So the problem is more about innovate than manage Microsoft.