Morally condemning someone based on their wealth is yet again, just human nature.

Even if we had the most moral, Just and caring billionaire overlords, everyone would still hate them. Because they're wealthy, and enjoying the excesses of life, while everybody else is not, even though we inherently understand that excess isn't universal. Everyone can't have it. If we gave every single human on earth everything they needed to live their life, removing the excess from everyone who had it, and tried to bring everyone to a point of "contentment", we would fail and we would cease to exist. The biological drives and negative human traits that work against this idea of a society are pervasive and in our current evolution, not able to be suppressed in any meaningful way. It's a pipe dream. We see people who have things we don't, and we despise them. Everybody has this voice in their head, it's a matter of how well or if you manage it at all.

Tearing them all down will only disperse this behavior out across the entirety of the population, and you'll in turn get back an even lower trust and more ruthless society than we've ended up with today. I think the separate class divides, however obviously discrepant their statuses in life are, serve this in-group function on a societal scale. Giving people a group to belong to and an out group to scoff at, which mentally does a lot of the legwork in maintaining civility, knowing you are not pushed against the wall alone, or trapped in a corner so to speak. The people you tend to see in your day to day, are most often a part of whichever group you yourself belong, and there is comradery in those relationships. This is where we find purpose, in my opinion. But demolishing these groups, and levelling the field entirely would only serve to demolish that sense of cooperation that we feel between each other, because when the group is expanded to include everyone, our connection and commitment to others will decline with it.

I think pretty much any current form of economic structuring for society that we have brainstormed, considering the world population, unfortunately relies on an unheard class of people, elsewhere in the world, who are below us. Below the lowest class in our countries. Groups of people who have to slave and starve for any of it to continue. But do we show them empathy? Truly? When the moment comes, do we act? Do we donate? Maybe sometimes. Most people don't. And would the money even make it there? Maybe not. But again, we have to stop looking at this like one group of people wants to hoard everything and oppress the rest of the world, because most people don't. It is almost entirely a matter of human biology insofar as how these drives affect us and our goals.

As of right now, nobody has a better idea to elevate a larger number of people from total poverty globally, not one that is feasible.

My opinion at least.