If we suddenly have large amounts of previously expensive (rare or difficult to extract) metals available, what will this do to commodity markets? Would prices be driven down? If the price of $mineral goes down below a certain level, demand has to go up for continued asteroid mining to be viable. What future activities (apart from the obvious, like catalytic converters) might provide this demand?
I'm by no means an expert on the topic, and I don't have any specific examples to cite, but it seems like an almost weekly occurrence to read about some cool new technology that will 'never' be economically viable, due to the cost of the 'unobtanium' required to mass produce it (holy long sentence batman...).
It seems likely that the end result of a massive influx of rare materials would simply make 'never' happen a whole lot sooner. While the price would obviously fall (likely by quite a significant amount, that's kinda the point), I doubt it would fall to the point of being 'worthless.'