Corrupt businesses can only do that if they’re in a situation without competition.
With competition in play, they can’t just push up prices arbitrarily without losing business to their competitors.
A situation without competition between businesses is more like a corrupted market. I guess the businesses are themselves corrupt too, to be participating in such a price fixing cartel, to take the opportunity provided by the corrupted market, but the only reason they’re able to is if their competition has been eliminated.