As far as I know the main reasons for bitcoin going down in price is because of the ICO and BITCOIN exchanger regulations that China is working on in their country. It may also be a result of some corrections in price.
You are very much right. I think the main reason behind so much decrease in the market price of Bitcoin is due to the involvement which China is taking. I think China wants to take control over all this and they want to rule Bitcoin. I think this is just a temporary downfall of Bitcoin and things will change in the future.