How much of the cost of these things are actually in energy consumption to manufacture. I can guess that the material cost for these is more than for a typical incandescent, but probably not by a factor, more likely double. The rest of the cost then has to be in energy used in production. I can buy (4) 75 watt light bulbs for about $1.29 if I do not care what brand I get, or I can buy (4) 100 watt light bulbs for as much as $6.95 if I want a high quality name brand. I can also buy some that are simply $5.95 each if I want 6500k 100 watt name brand. If you say the reason for the cost is simply more expensive materials to make them, why is the material so expensive? Is it because there is very limited available anywhere, or is it because it takes alot of energy to get it out of the environment and turned into a production ready substance? In the end, you can almost always trace the cost of an item back to the total energy required to produce it. While 50,000 hours is a long time, many times these things will be replaced long before they give out. From the time I was a child until I left for military my family probably turned in 5 TVs to salvation army in still working order. People upgrade, and at the rate that things change in todays society it is much more frequently. In the future it will probably be even more so. So while this light is nice today, and if you keep it for your lifetime it makes sense, but I say it is more likely it is like a computer, while you could probably spend $10,000 and have the fastest thing in crysis around, next year you will likely be dumping your old machine and upgrading to the next $10,000 machine that has new features. For lightbulbs the features could be light output, light color, dimmable, new fixtures specifically made for LED lighting, a higher efficiency solar panel or what ever. The likely hood of someone keeping these particular lights installed for decades is probably very minimal.