The price of Bitcoin is basically what the last person to buy it decided to pay for it. If the last person to buy it decided to pay one penny for one satoshi, then the price of Bitcoin would be one million dollars.
I think external influences such as government decisions and stakeholders also cause some major influence in determining Bitcoin prices.
This is basically due to the demand and supply of bitcoin, this causes price fluctuations and has little to go with the difficulties and the miners.