I think Toyota might be worried about flooding the market. If they're just barely making a profit on each sale, then they need to keep selling at MSRP, which means keeping supply much lower than demand. If they ramp up and sales go flat, it could be a big problem. Things like the transmission, electric motor, batteries and computers can't be used in their other models.
The only problem with that argument is that Toyota makes a flat price off of each sale no matter what - it's the dealer that raises the price from invoice to MSRP. They are the only ones making extra $$$ off of selling these cars at MSRP or over. Granted, there are times when rebates and whatnot kick in for certain models, but I don't think they are going to have to worry about doing that for the Prius anytime soon
