Not really sure why you inferred there was a cutoff. It's a gradual ramp-up, at some point between "enough to live the rest of their life in comfort" and short

Not really sure why you inferred there was a cutoff. It's a gradual ramp-up, at some point between "enough to live the rest of their life in comfort" and short of "one billion." The response wasn't meant to be a complete, self-contained argument that billionaires are terrible people as a step function; it was intended to allude to the well-known argument that you're terrible well before the $1B point. If you're not convinced by that argument or not interested in finding it, this conversation certainly isn't going to change your mind.