I think retaining key talent is one of Tim Cooks' most important jobs... and this shows pretty clearly that Mansfield was tired of his previous job, wanted to retire, and Tim found a way to create a position that interested him, or at least, would keep him around for a couple more years.
And this new section, I think, could be really important.
Apple has been really innovating in silicon and wireless technologies, and they're at a point where this will increasingly be the source of key competitive advantages.
I suspect Mansfield's job is to integrate this division, get it whipped into shape and then recruit a replacement to lead it.
Then Cook convinced Mansfield to "unretire" and become an advisor: http://gigaom.com/apple/shedding-light-on-apple-exec-drama-w...
And now, Mansfield heads up a huge new group called Technologies (wireless, semiconductor, etc).
What a roller coaster for Mansfield... but not just him, the entire management team because they're all working together and dependent on each other.