What made Windows viable was Microsoft's heavy investment in providing first class Apps with the Office suite. Arguably Google did this with email and maps apps for Android, but even feature phones have those. They're not a platform differentiator. With iOS you had Garageband, Pages, Numbers and even some first class thirdarty apps out within days of the launch of the App Store. Even now iOS has far more high quality apps and games than Android. If you were to look at comparative app availability and quality between iOS and Android now, and compare that to similar comparative metrics for Windows and Mac OS at similar stages in the 90s, iOS would look a lot more like Windows that it would look like MacOS, whatever you think about 'developer friendliness'. Android being more 'open' may make it more like windows in some ways, but so far that has still yet to translate into it moving ahead as an app platform, and even if/when it does that will no more spell doom for iOS than iOSs current success there spells doom for Android now.