I think you're forgetting to factor in the tail risks when calculating the rate. In fact I doubt they still qualify as "tail" under those circumstances. There's a fairly decent chance the retirement plan ends up being facing a firing squad.
We get less violent because AI research pays more than murder, so more people focus on being good AI researchers than good killers, and the world is happier for it.
Hitmen get what, $5-50k? And that’s for murder.