Two things that come to mind are inflation and demand. What is the value of the dollar of 20 years ago today? A dollar of 1984 would be worth almost $2 today, and demand has helped keep the price of available PVs high. When manufacturing catches up to demand, prices might drop, but I suspect that $1/watt PVs is in the same category as nuclear reactors producing electricity that is too cheap to meter.
I recently purchased some 125 panels for around $480 each, and I thought that was a reasonable price. We added a total of 1500 watts to our system, including a adjustable tilt rack, wiring for the 240 feet to the garage, a new Outback MX60 charge controller, and necessary circuit breakers, etc. We added it to our existing wind generator, pvs, batteries, and inverter.
The additional 1.5kw will cost us about $7500 to $8000 before any tax breaks, rebates, etc. We are making some changes in how we are using electricity, so I'm not sure yet how much power we will still be buying from the local utility, but I think that it is worth spending the money for reliability, safety, emergency power, and as a political statement.
Jim