Stalin already tried that tactic and it didn’t work

It didn’t? Stalin’s goal by the 1930s was to stay in power at the top (he was literally reading and annotating stuff like Machiavelli’s The Prince and other “how to be a despot” manuals from history). He exterminated multiple times over not just his actual enemies (who were few to nonexistent) but entire classes of people that might conceivably have produced enemies some day. And he died of natural causes (probably). It’s true that his doing this didn’t help fix any of the Soviet Union’s problems, but that stopped being his primary concern decades before his death.