Not that I've ever had much money, but let me provide some thinking of why this is the case.
When you have a lot of money, you are used to getting anything you want, since everything has a price. Want a hotel room overlooking Times Square for NYE? Sure, maybe it'll cost you $25K, but you can probably get it (I'm just guessing here). Want Madonna to come sing at your barbecue? Sure, that'll be a million bucks (plus incidentals).
So when a rich guy is without friends, his first reaction is "how much will it cost?". The moment he flashes his money, all sorts of "friends" come out of the woodwork, happy to be his chum. So, in the short term it looks like it's working. But these aren't friendships; these are hired companions. Just because you can hire a hooker to have sex with you doesn't make her your girlfriend.
One only has to look at the myriad NBA/NFL players out there who, despite having earned 100s of millions of dollars over their lifetimes, end up broke shortly after retiring (and this does not include child support). It's mainly because their wealth attracted the leeches who sucked them dry.