At mobile forums like this one, there is a lot of talk about the iPhone market size. The traditional wisdom is: if you want to make money selling mobile apps you have to develop for multiple platforms.
This is because of the fragmented mobile device market of which currently includes 10M iPhones or so.
Looking at only iPhones underestimates the Apple application market
Sure Apple sold 10M iphones in the last year, but what about the iPod Touch? It also runs apps. The iPod touch addresses a whole other market outside the cell phone market. I haven’t seen many sales estimates that include touch numbers however.
The richly featured iPod touch may be only be the start. The cost of materials for the iPhone has been reduced to only $174.33. With much lower component costs, Apple can now move features such as an accelerometer into lower end iPod models.
Mobile Platform Endgame
Apple will eventually extend the iPhone/touch OS platform backward into their entire product line. Apple has already sold 200M iPods and their batteries are slowly losing their ability to hold a charge. As consumers refresh their aging MP3 players, they will be phased on to apples new mobile version of OS X and apps such as more cowbell will gain whole new audiences to entertain.