Really? Years? It seems stuff in Qt-labs typically gets to the mainline a version or two later - maybe Qt 4.8?
It's never developers that make the decisions at this level - typically someone somewhere in the upper reaches of middle management who hasn't touched code for 5+ years. There's also a big difference between what people fear will happen in a re-org and what actually happens afterwards.
What about one of the comments on this thread, is DuiApplication really needed, or can things be pushed back into the private implementation of QApplication? I realise the libdui guys can't do that on their own, but in theory?