In the recent article by Peter Wayner of InfoWorld called iPhone development tools that work the way you do, he describes the value of using a mobile application SDK or framework. He lists 4 new toolkits to help mobile application developers develop applications faster for use on handheld PDAs and Smart phones. This is a market in which I am intimately familiar.
The challenge with the market for mobile application frameworks and SDKs is that very few developers want to spend money on an SDK from a small vendor, and even fewer companies want SDKs or are willing to fund long term custom development and support projects internally. Companies want a finished product that works with their ERPs, database and accounting applications. They don't want to invest in a non-standard mobile framework. They want mobile extensions to their enterprise applications. SAP is addressing this with their NetWeaver based mobile infrastructure. This provides SAP users with a standardized method for extending their applications out to mobile devices, but it does not address how to develop the mobile application code. This theoretically creates an opportunity for mobile SDK vendors.
Appforge and Dexterra are two very BIG examples of how challenging it is to be a successful vendor of mobile application frameworks and SDKs. It is yet to be proven that there can be a successful business model as the author of these mobile application frameworks, unless you are a giant like Microsoft or Apple. Dexterra bet the house that Microsoft would acquire them and they lost.
Now, it is true that to make these finished mobile software applications, there is a need for powerful mobile SDKs, but these SDKs are very costly to development and there is yet to be a good and proven business model for small independent vendors of such.
Some vendors of mobile application frameworks want to sell you a toolkit and then charge you a license fee for every mobile device you deploy on. This is not a good model, unless the application is an off-the-shelf mobile application. It makes sense to pay for syncing technology and mobile databases, but a per deployment model for code that you create is hard to swallow.
The biggest challenge vendors of mobile application frameworks and mobile SDKs face is getting the economies of scale that all software companies seek. Who is the real market? Developers? They seek to work in the sexy high profile technologies from the big name companies so they can pad their resumes. They do not want to take a chance on learning an SDK from a very small company that no one knows and they are unlikely able to leverage in the future. They may use an SDK to deliver their cool mobile application, but there is simply not enough of these developers willing to buy your SDK for significant amounts of money to be profitable.
Does the IT department in a company want to buy your SDK, a few but not enough to build a profitable long term software business as an SDK vendor. Again, companies will always seek a finished mobile application that extends their internal IT investment. If SAP has a mobile framework, they want that. If SAP didn't have the mobile extension, then the company would want a finished mobile application that is already integrated with SAP.
In summary, there are many examples of companies developing very cool mobile SDKs and mobile frameworks, but very few with successful business models. Companies want to extend internal applications with mobile extensions developed by the owner of their internal applications. In the event there are no mobile extensions from their key vendor, then they want a finished mobile application that is pre-integrated with their ERP or back-office applications. SDKs are cool, but a successful business model remains elusive.