Billionaires have stolen their funds by taking the vast majority of the wealth produced by their workers, the actual people making their companies profitable. While keeping their workers as close to the poverty line as possible. And then they and their cronies have bribed their way into favorable tax conditions so that they can keep all of their ill-gotten profits instead of paying their fair share of taxes. Taxes that should go back towards supporting all of the infrastructure that allowed them to exploit their workers so effectively. Roads, power grid, schools for their workers, hospitals, regulations keeping the world habitable, etc.
If billionaires had paid their fair share of taxes instead of stealing them to become so rich they have to invent new bullshit to spend it on, governments and the people would get to decide how to spend that money instead of allowing 1 rich asshole to decide the fate of the world. We could be using that money to push even more for renewables and get off coal. To build nuclear plants in less than 2 decades. For every 1 Gates who wants to gild his legacy of theft and coercion by curing some diseases, you have 100 Musks who tank things others have created or Waltons who ruin our competition and exploit workers and government both.
Billionaires are all, every last one, thieves. Billionaires are immoral and should not exist. Eat the fucking rich already and tax the shit out of them.