There are old words for this: Monopolies and Trusts. The US around this point last century put a lot of work in Trust-Busting and Anti-Monopoly/Anti-Corruption work.

The other related word is Oligarchy, rule by a select few that think they know better than everyone else. Oligarchy seems to be a failure case of most modes of politics and economics. Capitalism and communism both fail over to oligarchy when left unchecked.

It's been argued that for as many centuries as humanity spent under feudalism that oligarchy is almost the "default state" of politics and economics and it takes great effort to avoid it. Adam Smith saw economic monopolies and knew they were a failure case of capitalism from early on. Capitalism was built on top of breaking apart monopolies like the East India Trading Company. We've always known that capitalism is just as likely to slip into oligarchy as any other "ideal" form of resource allocation/economics, especially because it started as oligarchy.