Any comparison of the Microsoft / Apple wars to the iOS / Android wars needs to take into account one major difference: the presence of Steve Jobs.
Jobs left Apple in 1987, after which the company quickly became a stodgy computer company, a Dell wannabe. They lost their design mojo - anyone else here remember the dark days of all of the performas, and quadros and powermacs with impenetrable model numbers after the names? Beige boxes without any style running an increasingly creaky OS.
Jobs returned in 1997, and immediately the design chops came back, and the Mac's marketshare has been steadily climbing ever since, until today the Mac has enough presence in the US market that the platform is once again well supported by software and hardware vendors.
This time around, with the battle between iOS and Android, Apple is not as likely to drop the ball, like they did in the late 80s, early 90s. The end result, in my opinion, will be a market with two dominant platforms. Over time I would expect Android to become the budget choice with Apple picking off the high margin segment of the market. Indeed, this is the current market configuration that we see in the PC / Mac market.
Of course, the day is coming when Steve Jobs will no longer be at the helm of Apple. I would hope that the board has understood the lesson from the first Jobs-less period, by choosing a successor that understands the primacy of design for Apple.