What actually caused the collapse of Soviet Union and communism in Russia?

On March 17, 1991, the USSR conducted a referendum, asking people if they would like to remain in USSR, or go their separate ways. The result is below. The blue ones said "I want to stay as USSR", and the green ones said "I want to become an independent country".

Basically, the 3 Baltic countries wanted to gain independence. They were the richest, the most industrialized countries in USSR, and they were like "without USSR, we'd be like Germany!"

In the 5 -stans, i.e., Kazakhstan, Tajikistan, etc., were like "I want to remain as part of the USSR. Without the USSR, we'd be like Afghanistan!" 95% voted to stay with USSR.

The 3 central Slavic nations, i.e., Russia, Belarus, and Ukraine, were like around 75% pro-USSR, and 25% pro-independence.

This should not surprise you. The common people mostly don't like drastic changes unless their lives have become intolerable. The common people would most likely be concerned about "how will my job be affected?" "What's going to happen to my children's kindergarten?" "how will my pension be affected?" etc. There were no answers to any of these day-to-day questions.

So what happened? The people were told "You f*cking brainwashed idots! You don't know what's good for you!" The Russians, or the Russian elite, i.e., Yeltsin, wanted out. Economically, Russia had contributed more to the other republics than getting money back from the other republics, in exchange for the political influence in other countries. As money got tight, Russia wanted to drop the burden. Nobody, least of all, the "leader of democracy", gave a sh*t about "the will of the people".

On Dec. 8th, 1991, 9 months after the USSR Referendum, Yeltsin signed the Belavezha Accords and dissolved USSR with just 2 other republics:
The story was that Yeltsin got so drunk, that Shushkevich had to grab him by his arm when he almost fell down from the stairs. Nazarbayev of Kazakhstan didn't hear about it until 3 days later. He bawled his eyes out, packed up, went home, and declared independence 8 days later, on December 16th. Dissolution of the Soviet Union 

So what happened after the Dissolution?

The Baltic countries definitely made the economically correct move. All three of them now have higher GDP per capita than Russia.

The 5 -stans, without Russian injection of cash and technology, mostly did not fare so well, except Kazakhstan. Ironically, the republic which most abhor leaving USSR now have a GDP per capita close to Russia, thanks to the oil and gas exploration.

The original instigators, i.e., Russia, Ukraine, Belarus, all fared relatively poorly. All of them took at least 10 years to get back to where they were before, while the rest of the world has moved on... Ukraine in particular, 25 years later, is still below their 1990 level.

Here is the GDP per capita normalized to 1991 level for all former USSR republics. As you can see, almost half of them are still not getting back to their pre-1991 level. Source: Investing in Russia: a cross country comparison 

So you see, the people were, actually, more correct than the politicians. They knew that the Baltic countries would be better off, the Central Asian countries would very likely to be worse off, and the three Slavic countries, i.e., Russia, Ukraine, and Belarus, would more likely sink than swim. But there was nothing they could do about it. That's that. Democracies born out of unbelievably un-democratic political processes.

source :- quora.com