I agree that Apple will eventually go the route of Microsoft, Intel and IBM. They will enter the next phase of their maturity which is to become an income stock based company as opposed to being a growth story. I was having this discussion this morning with some inlaws who are all Apple fanboys. Only I own stock in the company but they all own everything Apple makes and one is an Apple certified engineer. I told them I felt Apple will be good for growth for another 2-3 years as long as they can keep up with the technology in the iphone and ipad, maybe catch up with the Apple TV. This will keep them strong because they presently do not hold a majority market share in anything. That means they have plenty of room to grow as long as they do not ever turn out a new product that is considered obsolete by competitor standards.
After reading the book Steve Jobs, I formed a different opinion of this psychopath! He was not really the genius creator everyone thought he was but rather a narcissist megalomaniac who took his talented people's ideas and told them they were "sh!t" then two weeks later called them into a meeting and said he had a brilliant idea where he took credit for telling them what his employee explained two week earlier. Consequently, I feel with these people still there, Apple will continue to generate new ideas for new game changing technology, but in the meantime existing products have to keep up or die!
Right now, the best thing to happen at Apple is Tim Cook. He is a much smarter businessman than Steve would ever hope to be. He is the right CEO for Apple right now.
As far as margins go, Apple, having a line of low cost iphones is very smart because it will hook new people into the Apple community. Apple is known for having the lowest churn in the industry. There seems to be no cure for Apple addiction. This will benefit the sale of other products as well. Most people aren't like us. They just want simple and easy where everything works together. Apple users aren't Macheads. They are "iHeads." (I stole that from one of my inlaws who used it to describe what the new Apple fanboys are.