How does mass formation perpetuate totalitarian regimes?
“In substance, the totalitarian leader is nothing more nor less than the functionary of the masses he leads; he is not a power-hungry individual imposing a tyrannical and arbitrary will upon his subjects. Being a mere functionary, he can be replaced at any time, and he depends just as much on the masses he embodies as the masses depend upon him.” -Hannah Arendt, The Origins of Totalitarianism
“Given this background, one could infer, if one did not know it already, the general structure of Oceanic society. At the apex of the pyramid comes Big Brother. Big Brother is infallible and all-powerful. Every success, every achievement, every victory, every scientific discovery, all knowledge, all wisdom, all happiness, all virtue, are held to issue directly from his leadership and inspiration. Nobody has ever seen Big Brother. He is a face on the hoardings, a voice on the telescreen. We may be reasonably sure that he will never die, and there is already considerable uncertainty as to when he was born. Big Brother is the guise in which the Party chooses to exhibit itself to the world. His function is to act as a focusing point for love, fear, and reverence, emotions which are more easily felt toward and individual than toward an organization.” -George Orwell, 1984
Unlike a dictatorship, the head of a totalitarian regime is an ideology. That makes it very hard to end the regime by simply toppling its titular leader. You must discredit the ideology or subsume it with another one.