My guess would simply be because the applications are limited in the West. Europe would have no demand for the technology as yearly lightning strikes can be less than .1/KM^2, while parts of the US can easily get to &#62;50/KM^2. Lots of Africa, and many parts of the southern hemisphere, can receive lightning strikes of &#62;200/KM^2 yearly.<p>Aside from the US and Australia, quite literally no technologically advanced country gets lightning on the scale needed for this to have the great potential it has. Even though much of Asia has high lightning strikes, China and Japan have virtually none. Leaving just India who would have the means to research something like this.<p>Honestly I believe the major problem is the current produced. A positive lightning strike can hit at 300kA, and electrical discharged requires a voltage of 3 million volts/meter traveled (IIRC a lightning bolt averages 100 million volts). This means to get it down to 110V, you're likely dealing with ~300 gigaAmperes. &#62;60 Amps will allow you to weld 16 gauge steel wire. So you would have to have enough conductive material to handle the flash-heating produced by a surge of 300gA. This flash heating may, however, be productive if use was intended for a power plant as it would provide massive amounts of flash-boiling.<p>Another problem, however, is that the receiver has to be high enough that no alternative route is provided to the lightning, or nothing will be received. However, creating an ionized path above the receiver (or multiple paths at 45 degrees away from the receiver) would enable it to 'catch' a lot of strikes, increasing strike rates.<p>I'd say it's certainly possible with present off the shelf technology, however I doubt its very practical and at worst, you could vaporize a lot of valuable copper.