I feel such arguments are so superficial. Billionaires are economical human anomalies. While they are easier to point and say that they are the cause of human greed and they need to do more for the society - IMO, the better question to ask is
1. how can we uplift the bottom echelon of the society and fix the systemic issues that put them in the poverty cycle.
2. Would we shit on billionaires and millionaires less if overall poverty in the world declines?
3. How can government programs become more efficient?
I just feel asking questions like 'should billionaires exist' do not push forward the discussion about bringing in systemic changes. Targetting them only gives a superfical understanding of what's wrong and gives an easy way out of the discussion.