Firstly, why assume that people don't want them. The first generation hybrid's drive very like conventional cars. By the second or third there will be so little difference as to be inconsequential. The only real bar to take-up will be people's opinions - but just look how the desirability of diesels has improved recently.
Secondly manufacturers need to work very hard at getting their vehicles to pass forthcoming emmissions laws. IVT can supposedly reduce fuel consumption by around 25% - obivously a great help in passing these emission controls. Hybrid cars improve fuel consumption by between 100 and 200%, and already pass all planned emissions laws. Which do you think the manufacturers will choose.
Bear in mind also that if/when an alternative source of generating electricity such as fuel cells becomes encomically viable, it will be much easier to convert a hybrid car than a conventional petrol one.
As I've said before, I have to doubt that IVT is a superb product, but the annoucement that production is not expected to start till 2007/2008 makes me think that they may simply be too late.