There are lots of reasons why the market value of bitcoins is going down. One of these are the external factors such as political policies like new laws and agreement.
Another thing is the demand in their services which slowly decreasing the market value when the demand falls down.
it is true your opinion bitcoin or crypto currency is unstable and is currently experiencing a decrease I think it has become a risk that we have understood from the beginning before starting with investment, I think that affects the price is also from bad news and the movement of sale and purchase of investors