People overestimate the role of propaganda. Complete media control could not save the Soviet Union. Further, when propaganda strays further from reality it can have a negative effect by feeding false info back to regime loyalists who become further divorced from reality.
The classic example here is the Ceacescu regime. Ceacescu did not realise until he was giving a speech to a vast crowd that his regime’s credibility had utterly collapsed. That is to say, unrealistic propaganda results in people buying their own bullshit.