Why are we arguing about the OS of a device? It is about the Apps. Microsoft knew this back in it's hayday. MS produced, copied, purchased, ran out of business useful and productive applications for it's platform. I think this monopolization of the software market by MS led to boredom with it's product and a lack of opportunity for developers with new ideas to successfully distribute new apps.
On the flip side I would argue that Steve Jobs followed Bill Gates is this respect. Apple has always been a locked down ecosyste - hardware and software. Choices were minimal. The Apple PC line never took off because it was too limited in the software choices available. With the iOS, Jobs "opened up" the platform to allow 3rd party developers. Thus we have all these really cool (and sometimes useful) apps. The plethora of choices in apps is what is making the IPhone and IPad so successful.