>

It partially boils down to Hobbes's idea of the social contract. 
Communism had a social contract with the population. You surrender individual sovereignty and we deliver improvement in material conditions to a point where we reach Utopia as described by Marx and Engels.
Once the cynicism sets in and the inevitability of utopia through Marxism gets replaced with Brezhnev's eternity of the same (the stagnation of the 1970s), the social contract fails. 
That is why Communism was gone by 1989 and 1991. It failed to uphold its own end of the social contract while the population gave up everything.  
I heard this comment before. Majority of the people believed till Chernobyl. Not after.
70 years later it collapsed >

69 years actually if we wanna be precise. 
Very nice! >

I like you, you are nice >

...and then it got worse. >

Ah a fellow Russian History buff >

A remarkable period of history it can be said. >

I've been reading Midnight in Chernobyl by Michael Higginbotham and its really incredible how the USSR operated vs what the people believed. While there was genuine support of the idea of a Utopia, the higher ups especially after Stalin didn't seem to think so, which is what brought the decline that would ultimately lead to the disaster and the fall of the union. 
Do I support the USSR? Not really but I do feel bad for the people  who achieved incredible things for nothing.