That's entirely dependent on the country and political culture. At the very least I can guaranty that in Britain, France and Germany public networks and new agencies are far more neutral and independent than private ones. And that's a result of political parties being unable to co-opt the administrative machinery of the government system. So they end up co-opting businessmen, who themselves control private media for influence.

In a well designed democracy nobody is strong enough for long enough to take over public media, the school system, the judiciary, the army etc.