just to point something important: caviar was abundant on Russia (which is hell big), so the whole USSR benefited from it. Right now it is expensive af not only because it is more expensive to produce, export, etc... but also because from a point of time it has been considered a luxury food and the price is most of it speculative.
In the USSR caviar was no luxury at all. For something to be considered luxury, it has to be "exclusive" as capitalist pigs say, and caviar was abundant.