Managers usually fire team members rather than take the fall for the team.
I think that's the point, you wouldn't see it. If a good manager gets unreasonably or unfairly reamed by his boss, he's probably not gonna tell his team about it, because it would be a blow to morale. If it was indeed the team's dysfunction, he'd try to improve it.
Meanwhile the most useless people are failing upward into CEO.
It's rare, but it does happen.
Correct. In addition, sometimes advocating for those under you is a sacrificial act, because you're putting your reputation on the line.
It sounds like the management philosophies at our respective orgs are very different.