If in earlier years Soviet Union was able to aid economies of these countries in order to support communist regimes, then starting from the years fro stagnation in late 1970's the situation changed. Findings were shortening and the U.S.S.R. was not able to support unprofitable industries of its partners as its own economy was experiencing troubles: The growth of the Soviet economy has been systematically decelerating since the 1950s as a consequence of dwindling supplies of new labor, the increasing cost of raw material inputs, and the constraints on factor productivity improvement imposed by the rigidities of the planning and management system. The average annual growth of Soviet GNP dropped from 5.3% in the late 1960s to 3.7% in the early 1970s, to 2.6% in the late 1970s. Soviet GNP grew by only 1.6% per annum in Brezhnev's last years (1979-82). After reaching a low in 1979, GNP growth averaged 2.3% from 1980 to 1984. Growth in 1985 will probably be in the range of 2.5 to 3.0%. These recent improvements have been the result largely of disciplinary and incentive measures introduced under Andropov and Gorbachev. It remains to be seen if the upturn in growth can be sustained...." (Berkowitz, 1995)

After the death of Leonid Brejnev it was clear that state and society demanded reforms in order to preserve the huge empire from collapse and catastrophe. Starting from 1985 new USSR leader Mikhail Gorbachev took a new course directed on democratization and liberalization of society, he initiated economic reforms, shortened huge military budget and allowed small business activity. At the same time the leaders of Eastern European states demanded from Moscow approval on the changes in their economic policies and slow transition to market relations in order to stimulate national economies and prevent coming economical crisis:

combination of reasons ultimately persuaded the Soviet leadership to allow Eastern Europe to break free. They included: the enormous economic cost revolved in continuing to sustain unpopular regimes (it has emerged, for instance, that the military regime of General Jaruzelski in Poland was subsidised to the tune of $2 billion and many billions of roubles from Moscow); the impossibility of competing with the United States in a renewed arms race which now included 'Star Wars' technology unavailable to the Soviets; and the need to attract Western investment and high-tech equipment." (Morewood, 1998)

By the end of 1980's it was clear that USSR, which was often called in American and European press -- empire of evil --, was living in agony. It was a huge super power without order inside. Late 1980's with relative freedom initiated the raise of nationalism in all republics where Russian population was an ethnic minority. At the same time inequality of ethnic representation in different brunches of power, in distribution of goods, etc. led to the wave of ethnic conflicts countrywide in a short period of time. Local officials, army officers and directors of industrial objects were all involved in deep corruption, which started in Kremlin and went down to small state farms and workshops. Number of state officials of different ranks were involved in ties with organized crime and mafia. The negative changes were obvious not only for Soviet citizens but for foreign observers and world community in general.

In 1988 both Gorbachev and Honecker said that Berlin wall would stand some 150 years more, but in CIA they knew that it was bluff. Gorbachev would have never used tanks against demonstrations in Poland, Czechoslovakia, Hungary or Eastern Germany. The level of relations with Western Europe and the U.S.A. was different, as it was becoming more and more clear that the U.S.S.R. was dependent upon export of oil and natural gas to Europe, it's own productive economy was not competitive. Even Soviet diplomatic manipulations with oil exporters of Middle East in 1970's didn't give positive results for Soviet geopolitics. Oil price growth only initiated technological modernization of European and American industry, while industry of the U.S.S.R. remained outdated, as...

That's why the events of 1989-1991 are often called the epoch of velvet revolutions in Eastern Europe.
If to look on this event from historical perspective we will find out that from the very beginning creation of buffer zone in Eastern Europe in the form of pro-soviet regimes of "people's democracy" was very expensive for the U.S.S.R. All those countries had long historical and cultural ties with other European countries; economies of Czechoslovakia, Hungary, Poland, Romania, Bulgaria and Yugoslavia were oriented on trade and business with Western partners, but not with Russia or Soviet Union in later years. Even though those Slav nations have much in common with Russian culture, they were always against Russian pan Slavism ideology, as they never coexisted in tight political, economical relations with Russia. No wonder those 45 years of communist regime were years of torments as communist ideology and principles of internationalism were alien to these nations. That's why the fall of Berlin wall and withdrawal of Soviet troops in 1989-1991 were the conclusion of logical process of unification with Europe. Russian Empire and later the U.S.S.R. was a state of a completely different political mentality. Russia was self- isolated from the rest of the world until the reforms of Peter the Great in the 18th century. Russian Orthodox mentality was completely different from European, it's enough to mention that serfdom in Europe disappeared 200-300 years earlier than in Russia and it's impossible to speak about civil society or even a nation (nations) in modern meaning of this word until the collapse of the Soviet Union. Because of it's huge territories and huge potential USSR was able to exist apart from the rest of the world without any dependence upon foreign imports for nearly 70 years. From this point the concept of command economy could suit USSR as well as Northern Korea, Mongolia, Vietnam and China to some extend due to the particularities of national mentality. But in the case with countries of Eastern Europe such approach failed to work as such political and economical ideology was even alien for their communist leaders.

Making a conclusion It's important to mark that Cold war as a result led to the collapse of one superpower (the U.S.S.R.) but at the same time it gave birth to successful development of Asian superpowers in the face of China and India, which have great chances to take of the leading roles in future geopolitics. From this point we can not say that the U.S.A. And NATO members "won" cold war. As D. Fleming writes:

The starting point should be a full recognition that this trend is not due to any mysteriously potent power in the virus of communism, but to the fundamental international anarchy which produced the two world wars. It was the wars, which loosed communist revolution from Moscow to Shanghai and to Stettin. Communism is not the cause of the West's loss of control over the vast bulk of Eurasia; it is the consequence."(Fleming, 1961)

References

Berkowitz, Bruce D. Richelson, Jeffrey T. The CIA vindicated: the Soviet collapse was predicted. The National Interest, No. 41, Fall 1995

Morewood, Steven Gorbachev and the Collapse of Communism History Review, No. 31, 1998

Fleming, D.F. The Cold War and Its Origins, 1917-1960 Vol. 2 Doubleday, 1961

Militant Vol. 61, no. 24. 23 June 1997

Secretary of State Madeleine Albright on Russia at the Carnegie Endowment for International Peace, Washington DC, 16 September 2000

William Curtis Wohlforth, The Elusive Balance of Power and Perceptions during the Cold war Ithaca, NY: Cornell University Press, 1993, chapters 4 and 5.

Dale Carter, Robin Clifton War and Cold War in American Foreign Policy, 1942-62 Palgrave, 1978

Joseph M. Siracusa, Into the Dark House: American Diplomacy and the Ideological Origins of the Cold War (Claremont, CA: Regina Books, 1998), pp. 155-56.

The Cold War in Retrospect: The Formative Years. Contributors: Roger S. Whitcomb - author. Publisher: Praeger Publishers. Place of Publication: Westport, CT. Publication Year: 1998 p.3

Powaski Ronald, The Cold War The United States and the Soviet Union 1917-1991 New York Oxford University Press 1998

How Did the Cold War Begin?