Yes it is very stable indeed 20K to 10K 
I can't imagine bitcoin with a stable price. But it seems it will be more stable overtime.
Bitcoin is decentralised cryptocurrency so it is not stable in a market. Because any time it will raise or fall in the crypto market it is just a common strategy of cryptocurrency. But it will be pump again in market it can't predict easily and no one should imagine the exact situation in crypto market. In current market is fluctuating 10k USD to 12k USD it will raise soon in market. I can't imagine bitcoin with a stable price. But it seems it will be more stable overtime.