Note the theory of second best - 2 monopolies (i.e. a union and the owner of a company town; or a health service and the monopoly owner of a patented drug) can

Note the theory of second best - 2 monopolies (i.e. a union and the owner of a company town; or a health service and the monopoly owner of a patented drug) can negotiate a better and fairer deal than 1 monopoly and a fragmented party. 2 fragmented parties is best (in theory), but that doesn't always happen. But most economists don't learn this in school. They just learn "monopoly = bad, government = monopoly".