Probably because if you can get it at or near spot on the open market, it's cheaper to buy it than mine it. It normally takes 5-7 years to start production on a new mine. Besides, with all those dollars in their bank that just about everyone knows are going to lose purchasing power diversification out of dollars into something that won't be losing value makes a lot of sense whether you are a capitalist or a communist. I know I am trading in as many of my dollars as I can afford for silver. And I don't think I'm alone.