I dont think they in reality do exist(or to be precise not the ones you think about). Most of the bilionares have their wealth tied to the stock so if they wanted for some reason to use a significant proportion of it they would have to sell their stocks which would crash their companies valuation if they even found enough pepole to buy those stocks,so i doubt they are bilionares in reality, alghtough certainly most of them could come up with a few hundred milions (or much much more if we are talking about actual asset like in case of elon musk buying Twitter , but that in reality Just changes the stock their net worth is tied to) . Now oligarhs and warlords from dictatorships and failed states are completely another thing and they likely by siphoning money from state owned companies actually are just that wealthy but we can all agree that they are pathological cases regardless of your political alignment. There are also a few cases of inherited wealth but those are rare beacuse as it turns out even if you have a butload of money you can Stil somehow spend it on stupid shit(not to mention the fact that bilionares and milionares tend to have quite a lot of children so that divides their wealth between them even further ) .

So as always its not as simple alghtough i definietly do agree that pepole nowadays tend to simp on wealthy pepole a bit too much. (alghtough it seems sentiment shifted through pandemic to eat the Rich category, but that might be Just my bubble of internet recomendations). They are still wealthy as f*. They really do not need another tax break and they Will indeed survive being taxed much more than ordinary citizens, it is after all the country and its pepole that allowed them to become so Rich in the first place(By the said country providing education or reasonable legislative framework protecting their Business or offering lower taxation when they were starting out) it is reasonable that they give something back through higer taxes. And bilionare/milionares charity is a tax break, Not a charity.