You should check out books by Arkady and Boris Strugatsky, Russian SF writers. Most of their books were written in the 60's and 70's, and some in the 80's. Many good ones sat on a shelf for decades, before they could be published. Several of their books have been translated into English. They are not so much about the fall of the USSR, since virtually nobody could have foreseen that, but they offer good insights into the daily life and the mindset of the Soviet people.
They do describe a number of possible futures in their books. One series takes place in the "Noon Universe", where the people of Earth live in a Communist-like society or Star-trek like society, where poverty is eliminated, and people strive to better themselves, and to be useful. However, in those books they sometimes describe Orwellian societies of other planets (somehow also populated by humans), which are eerily similar to the realities of life in the USSR. See Prisoners of Power, aka "The Inhabited Island", and Hard to be a god.
Since you are already familiar with the Strugatsky brothers, you should check out Moscow 2042 by Vladimir Voynovich. This is a satirical book about a possible future in 2042. The Soviet system was based on the idea of "building Socialism in a single country", which replaced the notion of the "world revolution", prevalent at the turn of the 20th century. "Moscow 2042" takes that to the extreme, and describes "Communism in a single city". Communism, of course, means "from each according to one's ability, to each according to one's needs". The catch is that one's needs are determined by the powers that be, and there are a number of "levels of needs". The book is hilarious, especially if you can read it in Russian. It is also a not-so-subtle jab at Aleksandr Solzhenitsyn.