I agree. On the other hand, however, it does start with the editorial staff. If you re-train them to the traditional standards of political neutrality then they, in turn, CAN control what the nuts and bolts 'journalists' DARE to present to them for their consideration.
The rot starts from the top down . . . and can also be fixed the same way. But then again -- as you suggested -- just firing everyone and then re-hiring, WITH meaningful professional standards, would also work.