Also this looks to be aiming for a different market than people that really need a whole house solar system or people who don't really need it but can afford the $4,000 out-of-pocket. Which actually is a bigger market, because most people don't have $4,000 handy and most people don't have a real immediate need for whole-house solar, but there are a LOT of people that want to decrease their energy bill or just REALLY want to "be green". The lower the price goes, the more people will buy solar panels, just based on the concept of having solar panels and being more sustainable.
For those that rent and want to be able to take their panels with them, it's a winner of a product idea.