You make a good point about the Soviet Union being able to hold on to the communist system for 70 years but I will offer some hopeful (partially) thoughts that suggest we are not heading for centuries or even decades of a centralized, socialist, oppressive system.
First, the Soviet Union greatly weakened due to economic inadequacies. The gov’t could not provide for the people, the people knew the gov’t did not work and neither did the people much work, and payments started to slow then stop. The economic stresses of years of negative gov’t cash flow have already presented gov’ts with critical levels of debt. Gov’t cannot shower much more largesse on the poor masses before quickly producing a bad economic situation for those masses. The Soviets could blame the rich people for a while and then WW2 distracted attention. The US socialists will have a harder time distracting blame.
Second, movements like the Hungarian, Czech, then Polish (successful) had to wait till after WW2 to get attention. The people were demanding what the gov’t claimed to be providing—if your people are restless the pressure increases. The economic situation in the US is already putting pressure on gov’t that will increase in the US in months and years to come. Unemployed people will become more restless—more people will experience unemployment.
Socialists tend to attack, violently, their dissenters. In the US, the dissenters are vocal and already anticipating attack. The US socialists are less militaristic, but not entirely so, than most other socialists. They may have a harder time with dissent.
US citizens have known freedom and its bounty. The contrast is already apparent between free society and the post-2008 US socialist gov’t system. Anyone who draws attention to the difference, especially if the economic situation worsens, will have increasing numbers of people in agreement. Even the socialist media will have a hard time repeating the message that the economy is “in recovery” and that capitalists are to blame if the situation produced by the socialists increasingly effects the average citizen. Note how it is increasingly harming young people looking for work—they are ripe for questioning socialism.
Just my 2 cents.