I suspect a lot of it has to do with who you surround yourself with, and how much agency you give them.
One word that rich people almost never hear, is “no.” Even really nice ones don't hear it often.
That means that almost any rectally-sourced, harebrained idea they squeeze out, is treated as genius, by their entourage.
I know a number of fairly wealthy people, and some of them won’t have anything to do with me, because I say the “N” word. Others, actually ask me what I think.
People rapidly learn that asking me for my input means getting an answer that is honest, but not one they might want to hear (and that answer might be "I don't know.").
They don’t always give it much weight, but at least they ask.
Those folks are not always the ones you might consider “nice,” though.
Just anectdata, though, and the community we share has some traits that reward Honesty and seeking counsel from others.
Do yourself a favour and read the Tom Bower biographies of him, e.g. Branson: Behind The Mask
In fact, you can a get a good understanding of him indirectly through the testimony in Tubular Bells: the Mike Oldfield storyhttps://www.youtube.com/watch?t=877&v=UQLDGpcgNTM e.g. John Giddings says of Branson "He was a chancer. He was prepared to gamble and go for it. He was percieved as a visionary, putting it all together, but really he was importing records illegally and flogging them, right? He was a second-hand car salesman."
Fun Fact: Richard Branson had such an antagonistic relationship with Mike Oldfield, that Oldfield included a segment in one of his albums where he plays a guitar with staccato notes that spelled out "Fuck Off R.B." in morse code[1], recording under Branson's own label.
That doesn't necessarily mean he was a not-nice person.
He's actually fairly well-known for treating his employees well. One of the reasons his TV show wasn't so popular, was because he wasn't into pitting the contestants against each other, and firing the losers.
There are tons of people who enter a field because they're rich, hire great people, connect those great people with money, and do very well.
There are also rich people who believe wealth qualifies them as subject matter experts, which tends to go less well...