But there were big problems in Soviet Union. Their economy was failing. Their leaders refused to make reforms to their command economy. They were falling behind the West. Three Soviet leaders died in three years before Gorbachev.
Gorbachev knew he had to reform the Soviet economy if he wanted to compete with the West. That was where he made mistakes. It fall apart like the house of cards.
Luza was politically liberal in the context of US domestic politics but was a staunch anticommunist. He thought that the Soviet Union was likely to prevail in the Cold War. He stated to me that before Reagan's election in 1980, Europe was on the verge of a deal with the USSR.
As Prof. Luza explained, Europe was to get iron clad security guarantees in return for abandoning NATO and giving the USSR and the Warsaw Pact access to European financing, technology, and markets. When I last saw Luza, his assessment was that with Reagan as president, the Soviet Union and communism might be defeated.
As it was, the Soviet Union did not fall apart like a house of cards. Reagan and his team pulled the supports out and gave the rotten edifice a hard shove.
For some interesting reading, peruse the Reagan era national security directives and memoranda that laid out the strategy in formal terms. They are available on the internet.