I've thought about this also... I think the price of mining could be an anchor to the price of bitcoin.

Why would someone pay $10,000 or $20,000 for a single bitcoin if they can buy a mining rig for, say, $15,000 which will get them a bitcoin in, say 6 days. If a single bitcoin will really be worth $100,000 or so as some have claimed, wouldn't it be logical to think a mining rig for producing a bitcoin would have to be about the same price? And if that's true, how high would the difficulty be? How much power consumption are we talking about?

Am I missing something obvious?