The interesting development, to me, is Elon Musk's announcement that his company has developed a solar cell that a) is cheaper than normal shingles (due to not breaking during shipment) and b) looks like normal roof shingles. When viewed straight on, as the sun would, it's transparent so the sunlight can get in. When viewed from the ground, they look opaque. They also have a home battery pack to store the solar energy for nighttime/cloudy days.

I'm still skeptical of your $40,000+ figure, but I do know that solar power is currently too pricey for me to install it in my house. Still, the price is constantly coming down. It won't be long before home solar energy is cheaper than the big power companies.