The price
under $300-$400 is the price range of Bitcoin for the current situation of adoption. With more adoption, the price will rise.
Well, more people will adopt Bitcoin if the price stabilizes. When more people adopt Bitcoin, the value will start shooting up again and subsequently cause the price to become unstable.
It seems like Bitcoin will have a hard time whichever way you look at it.
The value of bitcoin is based on its usefulness. At present, only few than 1 million people use it. The value is about $6bn. When 10 million people use it, the value will be $600 bn.