No, that's backward.  The cost of production of something doesn't determine its value.  If I dig deep holes in the morning, and fill them up in the afternoon, and spend $10 000,- on that, then these filled holes aren't worth $ 10 000,-.

With mining, normally, the cost of mining is the dependent variable as miners join (and increase difficulty, and hence cost of mining) as long as it is profitable, which depends on the price of the currency (and the amount of block reward).  So the cost of mining is a consequence of the market value, and not the other way around.

If tomorrow, and for the years to come, bitcoin's price would fall to $10,-, then the mining costs will also drop by a factor of 70, and the difficulty will go down accordingly.