Once again, the absurd idea that everyone is out to get everyone else (except for you, of course).
First, to you. If you don’t like them, you can fire them.
Second, to other DROs, who likewise must compete on the basis of efficiency, price, quality of service, and good reputation. None of which they will ever achive if they are bandit organizations.
Third, to third-party arbitors and watchdog groups.
Finally, to a well-armed general populace who does not want to be expropriated and abused by rogue DROs.
Essentially, a private DRO is accountable to everyone. A government is accountable to nobody, because they, by definition, have a monopoly on force and final decision-making power.
See above.
And I should ask a similar question about the state - what stops it simply becoming a gang of thugs with the exclusive right to rob and murder?
The answer is: nothing. Because that is what a state is, in fact - an organization with a monopoly on crime, and a good PR department.