[Andrew Richards] "Apple is selling far more Macs now than ever in it history (and that's mostly laptops), and they are still only a small fraction of their overall revenues which are utterly dominated by the iPhone and iPad."
A misconception in there? I think there's some confusion over unit sales vs revenue but these Apple April 2012 quarterly report show iPad and Mac revenue as very close. iPhone sales are many fold higher.
So when it comes to tablets specifically improving Mac sales may be an important offset if Apple losses some iPad sales to the Surface.
One may well say that Apple is very heavily dependent on iPhone sales and that would be their point of vulnerability.