I read somewhere that after Stalin's death, his successors wanted to make sure one-man rule would not return. They all had experienced first-hand how not even the highest ranking Polit-buro member had been safe from Stalin's vindictiveness. Therefore Khrushchev et al. ruled by committee. Then Khrushchev was deposed, so maybe power was diluted too much. Brezhnev et all reverted to a more authoritarian rule but never killed fellow communists again, and were not nearly as brutal as Stalin's regime.
Seems plausible.
I read somewhere that after Stalin's death, his successors wanted to make sure one-man rule would not return. They all had experienced first-hand how not even the highest ranking Polit-buro member had been safe from Stalin's vindictiveness. Therefore Khrushchev et al. ruled by committee. Then Khrushchev was deposed, so maybe power was diluted too much. Brezhnev et all reverted to a more authoritarian rule but never killed fellow communists again, and were not nearly as brutal as Stalin's regime.