The price of bitcoin is formed exclusively by supply and demand for it. Bitcoins are not secured by any tangible assets, but the same situation is with any Fiat currencies, rubles or dollars. It is wrong to assume that bitcoin is provided with electricity spent on its mining or the cost of a bitcoin farm. The difficulty of solving the cryptographic problem during mining varies according to the network hashrate used to find the latest 2016 bitcoin blocks. If the number of miners and the electricity consumed fall several times, then the complexity of mining will simply decrease and the process will stabilize again. So the value of bitcoin and its purchasing power lies only in the public's trust in it.