Peter in the comments section gets it:
"Never underestimate the greed of the ignorant. Trump, Musk and all the rest look to the era of the Robber Barons as not only the Gilded Age, but the Golden Age for the obscenely rich. They want those days more than they want the next dollar they can extort from a wage slave. And let's be real, their vision of government is one without Social Security, Medicare, Medicaid or any semblance of a social safety net. They would be happy if government existed only to pay for a police force and a massive military with only one job - to protect them from all perceived enemies, foreign and domestic."
This isn't entirely about bad math and that they'd have issues maintaining current spending, they don't want current spending. Just a police/military force to keep us poors in check and prevent "the foreign barbarians" from taking the "treasure" from the ownership class.