I think one of the factors that can affect the bitcoin price is bad news or FUD's that can holders sell their bitcoin because they think that the price of bitcoin will drop and the other factor is there are some group of a pump and dump that can manipulate the value of bitcoin and the other thing is there are many scammers out there that use bitcoin as their presentation that is why people didn't trust bitcoin because of this reason.
In my own opinion, the factors that can affect the value of bitcoin is the competitors (if have) because we all know that in a business it is the main hindrance in our success. And also the second factors that affects the value of bitcoin is the negative news about it that spread along the countries. If they know about the negative thoughts about bitcoin some of the users will become concious and the trust of them from the bitcoin become less. The third that affects the value of bitcoin is, misinterpretation of some issues of bitcoin like someone said that bitcoin is scam something like that.