The AC is absolutely right. While there are a lot of people out there who could do their jobs on an iPad, who'd want to? I COULD do my work on a tablet, but I promise you my productivitiy would plummet without my dual monitors, a decent IDE, and a real keyboard. Comparing iOS and Windows is like comparing apples to oranges. They both have their strengths, but in a real world scenario there sales of one should only have minimal impact on the sales of the other. This only looks bad for Microsoft if you buy the hype that tablets are going to kill off desktops, which is a pretty ridiculous idea. They may replace desktops for those people who only use their computer for web browsing and email, but for the rest of us it would be pretty painful to give up our desktops for tablets.
And what's this nonsense about Windows falling out of its throne? Seriously, a 2:1 ratio would leave Windows in a pretty dominant position. Think of it in terms of sports. What would you think of a game that ended with a score of 6-3? And when you look at the only Apple product that really directly competes with Windows in its area of dominance the ratio is 19:1.