It took about 3 years for most of the competition to catch up to what the iPhone launched as. Microsoft kept trying to ride the WP 6 train hoping the iPhone was going to flop and not become the next iPod. Eventually they had to do a major rewrite which put them a few years behind of iPhone. Oops. Blackberry Storm and Torch are both still below par and not even competitive against Android devices, let alone iPhone. Nokia never caught up at all with the iPhone.
Similar story is playing out with the iPad. Android is catching up on hardware, but not software ecosystem. Maybe that will be different in a year, but the market could certainly shape up to be more like the iPod dominance of music players than the iPhone/Android dominance of phones. Windows 8 will launch when? 2 or 3 years after the iPad. Sound familiar? Blackberry Playbook is out, but that's such a mess it's not worth discussing.
Steve Jobs was right back in 2007 and most of the market is still 2-3 years behind where Apple is.