Take the iPhone4 launch. A new phone with a slightly higher resolution screen, but significantly smaller than the existing competition. Their framing, with retina branding, switched the existing conversation from screen size, not to resolution even (where apple had a minor lead, that would be soon overtaken) to PPI! There was almost no discussion of PPI before this. Apple competitors were now framed as 'worse' if they included a screen with the same resolution but bigger! Insane!
Now fast-forward to 2012, and we have a new iPad marketed as 35% bigger screen (again they have found a metric that maximises the difference, which would normally be framed as the 7" vs 7.9"), no mention of resolution.
Apple would never even show a competitor on their site, because they are the market leader.. but see Mac vs PC for what happens when they are not.