Mr Forestall was seen by some as a possible future CEO of Apple, but the ascendance of Tim Cook has apparently thwarted that ambition.
While the company is close-lipped about the nature of Mr Forestall's departure (ie, did he quit or was he invited to resign), he will remain at Apple as an advisor to Mr Cook until 2013. That could either be an indication that the circumstances are not too acrimonious, or (if he has been made the fall guy for the shortcomings of Maps) a way of making sure he doesn't sign on with a competitor too soon.
Cause and effect are not easily distinguished, but the scrapping of the iOS leadership role has been accompanied by a redistribution of responsibilities among the senior executive team.
Jony Ive, senior vice president of industrial design, gains control over Apple's human interface efforts.
Whether his success with physical designs will be replicated remains to be seen, but the OS X UI has become fragmented over the years and there is optimism in some quarters that Mr Ive may take a strong lead and restore the consistency and usability that has been lost.
Eddy Cue, senior vice president of Internet software and services, will take on responsibility for Siri and Maps.
This puts control of all Apple's online services in one pair of hands. Despite some hiccups with the introduction of MobileMe and subsequently iCloud. Mr Cue's successes are generally regarded as outweighing any shortcomings.
Senior vice president of software engineering Craig Federighi is now in charge of iOS and OS X.
This makes sense given the common base of the two operating systems and Apple's recent efforts to unify them.
While Dan Riccio remains in the role of senior vice president of hardware engineering, the 'unretired' Bob Mansfield has been given the title of senior vice president for technologies, and will lead wireless and semiconductor development.
Mr Mansfield has agreed to remain at Apple at least until 2014.
John Browett, the company's head of retail is also leaving. Unlike the situation with Mr Forestall, a successor is being sought.
Mr Cook will take charge of the retail operation in the interim.