When Apple released their graphical OS, Windows had zero market share. Windows wasn't even a product, but even when it was - people didn't buy it to run DOS apps, they bought it to run Windows apps. It was cheaper and it worked well enough.
That's why Android is comparable to Windows here. It was released later than iOS which already had market share, any hardware vendor can integrate with it, like Windows...and it's more developer friendly, like Windows (compared to the Mac OS). It's also better than good enough, like Windows. And those will be the direct reasons that will eventually let Android overtake iOS as an application platform.