Honda is selling about half as many Insights as they had expected to... based on how well the prius has sold.
Honda likely to miss U.S. sales targets for Insight?
There is already a waiting list for the new Prius. If I remember correctly, Prius sales increased EVERY year from 43,000 cars in 2003 to 281,000 cars in 2007.
I think it's more because the Insight is a half-ass hybrid and looks so blatantly like the 2nd gen Prius that people don't want it.