The goal of a company is to make as much money as possible. If you want to get people to develop for your OS over another OS you have to give them an incentive

The goal of a company is to make as much money as possible. If you want to get people to develop for your OS over another OS you have to give them an incentive to do so. Using a cross-platform API disincentives one to only develop for Windows as now the benefits to using platform specific technologies available only to Windows has been marginalized. If they're going for lowest common denominator apis like HTML/JS, then you get subpar LCD applications that Apple can blow away via better support in native apps and Apple OS specific APIs for Objective-C/XCode. Windows devs will then feel like they can do better than HTML/JS and move over to Objective-C/XCode and Apple. In fact I'm strongly considering moving to the Apple camp after being a long time staunch MS supporter for my entire career.