The Future of Mobile Development

It seems pretty clear that the future of mobile development will be based around smartphones. Given the success of Android, RIM, iPhone, Symbian and WinMo platforms it doesn´t look like many device manufacturers will be heading back to the old days of custom OS builds (Motorola, Sony you´ve done well with your own firmware in the past but its time now.). This report highlights the growth of mobile applications based on smart phones.

So the question is, Given that smartphone users are many times more likely to download and pay for mobile applications is there any point in developing for the mass-market phones anymore?