I'm not sure, and I can only suggest that you review the Thinlet forum archives, but I would dare say that MANY people still need the extremely thin client, mobile phones aren't THAT powerful (check the MIDP 1.0 spec.. yes, 2.0 is out, but hardware doesn't change as fast as new specs) and that part of Thinlet's wonderfullly small size comes from its one class nature.
Just something for consideration.