Decentralized bitcoin can never be stable. While its price depends on the supply-demand ratio in the market, it will constantly have high volatility. And the higher it will grow in price, the higher will be its volatility and the more risky it will be to invest. This can not be changed if no one maintains its price. Therefore, decentralized crypto currency will always be volatile in price, only centralized crypto currency has the ability to be more or less stable in price.