With this article, you'd think they'd just discovered GaN. It's been around for some time, about as long as there've been cheap blue and violet LED's and laser

With this article, you'd think they'd just discovered GaN. It's been around for some time, about as long as there've been cheap blue and violet LED's and lasers (your Blu-ray player uses GaN). Si may be an inferior semiconductor from certain performance perspectives, but it will just about always be cheaper. Gallium is pretty rare as elements go, and many other industries (including solar) consume a fair amount of it. You'll run out before you get it past niche applications.