The culmination of Gorbachev's glasnost and perestroika was the Fall of the Berlin Wall, one of the more memorable historical moments of the 20th century and one which gave a lot of hope to young people who grew up under the constant threat of nuclear annihilation. If you watched "The Day After Tomorrow" on American television in the 1980s, you might know the feeling.
However, in retrospect that was a high point in terms of hopes for peace and prosperity. The Soviet Union went rapidly from communist authoritarian to oligarch kleptocracy during the Yeltsin era, and NATO wasn't disbanded like the Warsaw Pact was but instead started bombing Europe (Yugoslavia), and the steady downhill progression has continued ever since. Putin threw out or jailed the oligarchs Washington preferred by 2005 or so, and since then it's been a steady return to full on Cold War proxy wars and gas and oil pipeline control conflicts (Georgia, Syria, Azerbaijan, Ukraine) stretching from the Middle East to Northern Europe.
It's ridiculous that after all those peace efforts in the late 1980s, we're back to early 1980s levels of nuclear tension. As far as who to blame, there's plenty to go around - oil corporations wanting more profits, arms dealers wanting more wars, authoritarians wanting more power, empires wanting more control of resources, etc.