Rather than speculating on how high bitcoins will skyrocket, how long will it take for them to become as stable as, say, USD?
Bitcoin will never become stable because its not tied to any material, accountable value beyond supply-demand and it doesn't have a central bank to support it and make swings less volatile... A god example would be a garden without a gardener, no matter how good it is underneath, someone has do to the necessary house keeping to keep it in shape.