I agree it would be hard to be so smooth again. But would they consider making the iPod Touch bigger but not the iPhone? It solves the problem of holding something big up to your face, since it doesn't take calls.
How does he know the people aren't buying the domestic cellphones because they're domestic? Even if they have larger screens, maybe that's not the reason people are buying them, maybe they're just being patriotic.
I do agree they need to allocate more dev resources to OS X, it seems like they only fix critical bugs these days. But overall OS X is a fine product, if you want to see what real bugginess looks like, try using a Linux distro for a week, even one that focuses on stability such as Ubuntu LTS.
I don't think the Halo Effect is the only explanation. Another one is that the PC market in general is not shrinking, it's specifically the low-cost PC market that is shrinking (being displaced by tablets). So the Mac is not escaping the shrinking of it's market, because it's not in the low-cost PC market in the first place. And since it's not escaping anything, there's no need to hypothesize Halo Effects and such to explain why it is escaping.
I think Bill Gates, and other people who underestimated the iPad, underestimated the importance of mobility in opening up new applications for computers. Apple's Life on iPad videos show this. I wonder if people who are underestimating the impact of a wristwatch computer are making the same mistake?