Moscow was supplied much often and better than rest of the towns around Moscow, and so forth. It was common practice to ride to Moscow to buy something that is not available locally. Moscow was number 1 in supply line, Moscow region and capital cities of other republics was number 2, European cities are number 3, rest was number 4 or (in practice) even lower, so it was expected that someone in Siberia, far far away from Moscow, never saw a good quality product for his whole life. Butter was example of high quality product, while margarine was low quality substitute which was widely available.
Dear, I am married to a girl from Omsk, and my son was born there. I know very well, that muscovites never had a glimpse of riches taiga and rivers provides to those living in Siberia. Good quality products were always abundant as the Sun there. You just had to know the right people.