Ruble need a couple of years to loose it majority of his value against dollar but have you checked the BTC price it can go upto 1000+ and can come back to 100 within a couple of months.
You can't compare a small community based economy like bitcoin with the biggest nation in world (land wise), in fact it proved that how stable bitcoin is
No matter how large an economy is, there will always be large whales manipulating the market. In Ruble's case, the FED is such manipulator, they printed trillions of money, those money went to middle east and sent the oil price above $120, and then they stopped printing, crashed oil price and dragged down Ruble
So you can anticipate that exchange rate manipulation will always happen regardless how large the economy is, since the fiat money can be created at will. But in bitcoin's case, since no one can create coin out of thin air, if it is widely used, the degree of market manipulation will be magnitudes lower