The iPhone and iPad are only tools, of which other competitors are making major inroads, i.e. the new Samsung Galaxy III came out months before Apples iPhone 5, which only had catch up upgrades. Without Steve Job's at the helm, expect more of the same.
Android holds the largest share of the Smart Phone market and growing, and android pads will follow that growth, think Amazon's release of the $199 pad with android and easy access to shopping their site.
What are Apple's possible future markets?
*Animation is dominated by Disney and Pixar.
* Music is dominated by Apple , but Amazon, Google and Spotify are coming to capture their share of the market.
* Books are dominated by Amazon.
* Online shopping is dominated by Amazon.
* Information/search technology is dominated by Google.
* Social networks are dominated by Facebook
* Auction's are dominated by EBay
* Movie on demand is a fragmented market, dominated by Cable, Satellite, Netflix, Youtube, Hulu, Cell carriers etc.
* Smart TV's will be developed by current TV manufacturers like Samsung.
* Smart cars will be developed by Google and current car manufacturers.
* Cloud computing is currently dominated by Google, Amazon, Microsoft and IBM.
Why would I pay to store my music on iTunes when for a monthly fee on Spotify, I can listen to anything I want on any devise, anytime.
Unless Apple is going to invent a transporter like on Star Trek, or a food materializer like on the Jetsons, I see only the iPhone and iPad to maintain a $700 billion market cap, of which multitudes of companies are rushing towards them.
The low hanging fruit has been captured, and the future could be bleak. Upgrades to these devises will sustain Apple for a several years, but after that, look out below.