What could've saved or changed the Soviet Union in terms of reforms?

I'm currently on about what things could've helped the Soviet Union not fall under leadership of Khrushchev, Brezhnev and Gorbachev or what reforms and changes could've saved the Soviet Union or is its rigidity of the Soviet system and the revisionist power of people like Khrushchev and the nomenklature too strong?

I'm asking in a way to help construct or at least feel satisfied with keeping the Soviet Union still exist in fiction.