It makes sense (in retrospect; I am certainly not an analyst who predicted this beforehand). Right now, it is more or less impossible for any Russian to a) use

It makes sense (in retrospect; I am certainly not an analyst who predicted this beforehand). Right now, it is more or less impossible for any Russian to a) use the dollar to buy anything from outside Russia, and b) travel outside Russia to buy anything in the first place. That greatly reduces the demand for exchanging rubles for dollars. This is true, whether via official or unofficial means. Consider Argentina, a country that for years has had its own serious economic issues. A huge skew between the official and black-market exchange rate for hard currency, such as in Argentina (the "dolar azul"), exists because a) there are capital controls but b) it's still possible to use those dollars/Euro/Swiss franc/whatever. Argentineans are free to use the US dollar to buy things, both inside and outside Argentina. This is not true for Russians.