For the same reason we don’t eat other predators. Billionaire diets consist of a lot of poor people who are high in mercury. Eating too much Billionaire would risk getting severe mercury poisoning as thier bodies store a lot of the mercury from their diet. Really it’s very dangerous to eat carnivores or any predators at the same level or above you on the food chain because mercury levels increase the higher you get. There is also a strong risk of developing a prion disease, which if you don’t know what that is look it up and be horrified.

The real question is why don’t billionaires eat more millionaires?

Perhaps they’re saving it for sweeps.

They’d die of several venereal diseases, given the bullshit-rich diet of billionaires

Undead don’t feed off of other undead. They drain the life-force from the living.

Billionaires need to exploit the labour of the masses, so they’re not interested in other billionaires. Because other billionaires don’t work