While development costs are one aspect of the complexity that having multiple platforms entails, a larger problem would be to encourage adoption beyond the early adopters and uber geeks, for creating an efficient billing platform is certainly no stroll in the park. Most of these app stores have exhibited an intention of cutting off the mobile operator from the picture, thereby complicating the billing mechanisms, and consequently risk alienating significant portion of the user base that would prefer the convenience of tying all mobile-based purchases to the carrier bill. And this is where mobile operators believe they can drive home their advantage. The announcements from China Mobile and Verizon need to be seen in this light. AT&T as well appears to be taking early steps with its App Beta program. In Europe, Orange too appears to be hitching the app store bandwagon.
The success that Apple has seen can be clearly traced to the virtually complete control that it has of the value chain; right from the device to the software, to the iTunes interface, to the payment mechanism, and in some cases, down to the operator (thro' exclusive agreements) ! However, the same is not really viable/practicable for any of the other new entrants. Fragmentation is a reality that they have to adapt to. And consequently, they might never be in the same league of the Apple app store. And more importantly, whether they like it or not, it will indeed be very challenging for either content companies or device vendors to create alternate mobile payment gateways bypassing the carrier billing.
The app store phenomenon will likely act as the final nail in the coffin for operator walled gardens. It remains to be seen how operators ensure they can find their collective bearings and work towards creating an ecosystem that offers value to the customer and monies to their pockets !