WHAT IF UMPIRES OWNED BASEBALL TEAMS?
If you knew that baseball teams with winning records tended to be more profitable for their owners than those with losing records - and if you learned that the Baltimore Orioles had just been purchased by the World Umpires Association (MLB's umpire's union), would you expect the Orioles to win more or fewer games?
Almost everyone implicitly understands why the umpires should not be allowed to own teams they referee.
In a free-market economic system, the government is supposed to be the umpire and not a player. Its job is to set and enforce the rules, but if it is allowed to also become a player, by owning and managing business enterprises, it is unlikely to treat the competing companies fairly, and there will be little check on its own misbehavior.
The record of government ownership and/or control of companies in the United States and elsewhere has been one long disaster. This promises to continue, and far more disatrously.

