There is a once famous book written in 1970 by Andrei Amalrik, titled
"Will Soviet Union survive until 1984?"
English edition: Harper and Row, NY, 1970.
(I don't think it was ever published in Russian. The author is an emigrant from
Soviet Union).
The date of his prediction is slightly incorrect, but in 1970s this was
a very unusual prediction, people did not believe him. The details and reasons
of collapse that he describes are all wrong.
When it actually collapsed, I tried to find whether there is any published text
of 1970s or 1980s which predicted this, and I found none, except this book.
Neither I could find any convincing explanation of reasons of this collapse.
Why China does not collapse?
I lived in Soviet Union, and talked to many people. Nobody could see this
before 1989.
Pemark.
The other answer mentions decline of oil production. This does not logically imply a dissolution of Soviet Union. (Cuba and N Korea have little oil, but they still exist). Decline of revenues from export may mean an economic crisis. But I believe that dissolution of Soviet Union had other reasons. Most countries which experience economic difficulties do not fall apart as a result.