It seems like much of it is rooted in methods that have kind of fallen by the wayside due to the incredible success of modern techniques.
TBH, that's one reason I find this interesting to begin with. It's a pet interest (obsession?) of mine to look for ideas that have been "left behind" and forgotten about prematurely for whatever reason. I suspect that from time to time there's a technique / idea / whatever lying out there in the sands of history just waiting for somebody to pick it up, dust it off, and turn it into something amazing.