There isn't a single right answer to that and I'm not going to suggest there is.

How any organisation operates, be that public or private, is down to the culture of the organisation, and culture comes from people, process, motivation, legislation, and a whole bunch of factors.

If an organisation has a clear mission, is held organisationally accountable in appropriate ways to that mission and makes people feel professionally enriched and valuable, it will attract competent people. And importantly, an organisation full of competent and principled individuals will attract other competent individuals.

On the flip side, if an organisation is subject to decades of mismanagement, has very poor oversight, doesn't reward people for being good at their jobs and in fact rewards the wrong behaviours then exactly the opposite will happen. People who are competent at what they do will either leave or be crushed down, while those who know how to play the bootlicking game will be raised up, and this type of organisation again becomes self-perpetuating.

None of this happens overnight, in either direction. Failure can take years or decades, and so can the reverse.