Your argument doesn't make any sense. 1) I don't think anyone ever claimed Apples was discontinuing OSX, just that it seems clear that it's taking a back seat,

Your argument doesn't make any sense. 1) I don't think anyone ever claimed Apples was discontinuing OSX, just that it seems clear that it's taking a back seat, both marketing and engineering wise, to the iPhone/iOS line of products. 2) If Xcode did run on Linux or Windows, that wouldn't reduce the lockin between Xcode and iOS. The inability to write iOS applications in a higher level language and target different phone backends has absolutely nothing to do with XCode running on OSX, and everything to do with the iPhone developer agreement specifically preventing you from doing so.