"Abolish billionaires" doesn't mean "kill anyone you want as long as you catch a couple of billionaires in the explosion." In fact, it doesn't mean "kill billionaires". It means tax them until they're not billionaires.
The worst part is that their assets are going to simply be bestowed on whoever whatever entity it was willed, and the accumulation itself is the problem, so even the actual supposed benefit is zero. Killing billionaires only makes the actual disparity more inefficient, you have to break up that wealth in a real way for it to be good at all.