A solar installation is an investment. The proper analysis is return on investment. Current actual price before credits and rebates for a 4kW rooftop (16 panels, abt 25 m^2), installed, is about $16,000. This includes a substantial profit for the installer -- it should be available for less in a competitive market...
It isn't the cost of the hardware that's preventing wider adoption. It is the completely ridiculous cost of installation which can easily double to triple the price. A number of states won't allow you to install your own panels and then hire an electrician to finish connection to the grid. You have to get a "certified" installer.
As an example, a 5KW system costs around $9000. The estimate I got for installing the system was $23,000, an additional $14,000 for installation. This is literally for a single day of work. In comparison, to get my whole roof replaced took 2 days and ran me about $8000 total.
If I were allowed to install my own panels, it would take me and a buddy about a day to do, and then have a certified electrician come in and finish wiring everything up. Total cost would be beer, pizza, and about $1000 tops for the electrician. But I'm not allowed to do that, so I either get fleeced by a lease or get gouged by the installation companies. No thanks.
The profit margins must be pretty damn sweet though. Easy money.