What you're describing is the theorised end state of capitalism. See crony-capitalism, state-capitalism, plutocracy, kakistrocracy, kleptocracy.

You can still own private property in a world that outlaws billionaires, requires strong redistribution of wealth, and ensures every large enterprise is democratic, instead of plutocratic. Reality is not binary. But if you don't accept that the existence of an ultra wealthy elite is an anti-democratic threat to the life and liberty of everyone — to the rule of law and social contract — you're gonna end up in an authoritarian fascist or communist hellscape run by megalomaniacal psychopaths who don't care about you, cut from the same cloth as each other. You can either support things that benefit the majority, or boot lick the criminally corrupt. If you choose to lick the boot, don't be a petty little bitch and complain when the world comes crashing down around you.