It’s sad to see Red Five Labs have ceased business activities. They used to produce a .NET runtime for Symbian phones. This allowed development of Symbian applications using Visual Studio .NET.
The fate of Red Five Labs is similar to Appforge. It’s difficult to make money from developers who are used to using free tools. The alternative of paying for the runtime on end users’ phones also isn’t viable. Generally, it’s difficult to make money from 3rd party mobile development tools, especially as the OS vendors and handset manufacturers are already providing them for free.
Meanwhile, there are (too) many ‘write it in html’ type tools that promise to create iPhone and Android applications but they really are too simplistic to create many types of commercial application. The demise of Red Five Labs and Appforge also shows the risk with using these third party tools. How long will they be around to support you?
Nevertheless, I believe there would be a huge market for a cross platform application generator. What I mean by this is something where you can write once and deploy (native) to many platforms and still retain the OS look and feel. Also, something that covers the majority of the native APIs. Such a thing wouldn’t be easy to produce. For example, just look at the difficulties (and timescales) Nokia is experiencing adapting Qt for Symbian and Maemo (see my related posts below).