Buffet doesn't have a vault full of 71bn dollar notes. His wealth almost entirely consists of the ownership of Berkshire Hathaway stock. That means that wealth consists of factories, media companies, property, mines, shops, warehouses and hundreds of thousands of people doing productive work.
So by and large, and there are exceptions of course, most billionaires are so because they lead and own huge businesses doing work on which our entire civilisation depends. They gained that control through being effective leaders that know how to build efficient and productive enterprises that employ people like you and me.
So what's the alternative? Appropriating their wealth would also involve removing their ownership and leadership of those businesses, and handing it to who? On what pretext, and to who's benefit?
Personally I have no problem with people being successful like that. What I think can be a problem is what happens to that wealth when those people die. If a person obtains vast wealth through hard work and contributing to society that's fine, but inheriting that kind of wealth is a different question. I think there's a reasonable case to be made for much higher inheritance taxes and regulation of trust funds.
Billion and it's larger cousin, Trillion(etc and so forth), really are hard for the human mind to grasp.
From: https://betterexplained.com/articles/how-to-develop-a-sense-...
One strategy is to rescale. So, if I am worth 1 million (I wish!) then someone worth 1 billion could treat things as though they were 1000 times cheaper than me. If you could get a $1000 per night hotel for $1 per night, that might change how you live. Further examples left to the reader.
If you listen to Marxists, employing people to do anything you yourself benefit from is inherently abusive. Property is theft!
Or you could ask my father in law what he thinks about that, having grown up under Mao.