It's not healthy for society. If you can't understand why, take it further, imagine instead that Musk manages to somehow accumulate far more wealth. He takes massive ownership stakes in every company. He buys out, or locks out through political influence, competitors, market by market until they fail/sell.
He could buy out the media. If they won't sell, since he owns so many major companies, he pulls advertising. He slaps them with as many lawsuits as he can throw at them until they cannot sustain themselves, and must do as he says or sell.
He'd have enough money to basically purchase any political race with ease. Between that and having the media doing his bidding, democracy is effectively dead.
Imagine he decides to offer insane amounts of money to start buying all of the farms and ranches. Now he controls the food supply. Where it goes. Who gets it. What they have to pay for it.
Wealth begets wealth. The more wealth you have, the faster your wealth grows, and the more disproportionately it grows compared to normal, working folks. A society which allows trillionaires while the bottom 50% are struggling to pay bills and wondering if they'll even be able to retire is a society that is headed rapidly towards failure. I suspect if there was a hypothetical communist multi-trillionaire that y'all would quickly realize how scary someone possessing that much wealth truly is.
Why do the liberals feel like they're entitled to Elon Musk's money? I don't get it