Horace Dediu analyzing iOS and Microsoft:
Microsoft invented the software business and built it to become the world’s most valuable business by the year 2000. It’s still been growing since and after 35 years it is reaching a profit of $27 billion per year. It did this while maintaining enormous margins and a highly disruptive monopoly business model the likes of which the world had never seen before.
It is scarcely believable then that a device business has been created to overtake it in four years.
You should really take a look at the entire post, it is amazing to see just how big iOS has become in such a (very) short time.