I don't agree with Adam Smith.
Bitcoin price is being determined by the free market, it worth what people are willing to pay for it.
The more the bitcoin price goes up, the more it becomes profitable to mine, which makes more miners to join the circulation, which increases the difficulty of mining a bitcoin, and makes it cost more to mine.
I think that the price of something is only related to how much people want it and are willing to pay for it.
During last year bitcoin miners were not really getting a lot out of mining bitcoins but with the recent surge in the price of bitcoin, mining bitcoins has become even more profitable then it used to be and now miners who have spent a lot on their mining equipments are actually making money, bitcoin mining is no longer a hobby but a profitable venture.