To Tyll's credit, he predicted that we'd see the tech come much more strongly into the headphone space in the future when he was on his way out from InnerFidelity.
Apple doesn't seem to be doing personal HRTF in the sense that Tyll predicted, but they do seem to be doing some kind of equalization based on sound interactions from inside the ear cups to fix sonic deficiencies and enhance noise cancellation.
Makes sense. If you can't get there with electrical and acoustic engineering then use EQ to make up a lot of the difference.
I think I might take the plunge.