It's hard to see Bitcoin having a stable price until all coins are mined. With the supply and demand and circulation changing it's not easy or impossible to have a stable price for bitcoin. Sometime we've seen wallets , exchanges and certain ICO's put a average price for Bitcoin or ethereum to exchange  other than that any tokens price will be on rapid changes when they traded in the market.

Until all BTC are mined it will still be volatile. Best shot we have to see how a stable price for a crypto currency would work is check out the price change of a token or coin that's already fully pumped to the market. until that happens this advantage and disadvantage is here to stay.